Air-tucking Needle
see Twin Needle
Antitherm
see PH-TE Needle

ARESW
Operation:
A swaged needle blank is run through a machine with five separate operations comprising the following (fig. 001):

Arm-bed Sewing Machine
The flat base plate is replaced by an elevated rounded arm (fig. 002). This machine is used for attaching sleeves or trouser shoe guards. We distinguish between: short arm-bed, long-arm bed and feed-off the arm machines.

Assembly Seam
Type of seam used to assemble two or more plies of fabric at a certain distance from the edge.

Attaching Seam
Type of seam used to join two or more plies of fabric. E.g. basting, pick stitching, trimming

Ball Points
Round points with a ball-shaped tip (fig. 003). Their task is to avoid, or at least reduce damage to the fabric. We can distinguish between the following types:

1. Light Ball Point

• 1.1 Construction:
        The spherical round point starts to taper to a pointed cone just above the eye. The tip is semi-spherical; it's diameter is approx. 10% of the blade's diameter.
• 1.2 Symbol:
        R-SES
• 1.3 Application:
        Sewing closely woven fabrics or knitted goods.

2. Medium Ball Point

• 2.1 Construction:
         The medium ball point starts to taper to a pointed cone shortly above the eye. The tip is semi-spherical; it's diameter is approx. 20% of the blade's diameter.
• 2.2 Symbol:
        R-SUK
• 2.3 Application:
        Sewing foundation garments and knitted goods.

3. Heavy Ball Point

• 3.1 Construction:
         The heavy ball point starts to taper to a pointed cone shortly above the eye. The tip is semi-spherical; with a diameter of approx. 30% of the blade's diameter.
• 3.2 Symbol:
         R-SKF
• 3.3 Application:
        Sewing foundation garments.

4. Extra Heavy Ball Point

• 4.1 Construction:
         The extra heavy ball point starts to taper to a pointed cone in the last third of the eye. The tip is semi-spherical with a diameter of approx. 70% of the blades's diameter.
• 4.2 Symbol:
        R-TR
• 4.3 Application:
        Embroidering tulle (net). The extra heavy ball point reduces the danger of the needle penetrating the connecting points and damaging the tulle thread.

5. Special Ball Point

• 5.1 Construction:
         The special ball point starts to taper to a pointed cone shortly above the eye. The tip has a diameter of approx. 60% of the blade's diameter. It is ground at an obtuse angle.
• 5.2 Symbol:
        R-SKL
• 5.3 Application:
        Used for sewing foundation garments (Lycra)

Bar
Linking piece made of thermo-plastic for twin or triplet needles.

Base Structure Sewing Machine
Sewing machine with a base plate that is raised considerably higher than the sewing machine table. The base is closed on all sides (fig. 004).

Basting
Temporary stitching of fabric with long stitches and coarse thread.

Bending

Operation:
1. Curved Needles
Intentional bending by pressing or rolling so that the blade or blade/shank are curved (fig. 005). (see Calibrating)

2. Point Bending
Intentional bending of the needle point into an excentric position (fig. 006). This process is used on needles upto a certain size and point length. Otherwise the excentric points are ground.

Bending Length
The distance between the clamping device and the point at which the force (F) is applied in the bending test (fig. 007).
Symbol: BL
Unit: Millimeter (mm)

Bending Properties
The main meaning of the behaviour of sewing machine needles when exposed to bending forces. The bending properties are the elastic limit, the force required to reach this limit, the breaking angle and the breaking force which are determined in a bending test.

The bending properties are influenced by:

• The geometry of the needle (i.e. length of shank, supplementary shoulder, one or double groove needle, needle size)
• Heat treatment
• Mechanical surface treatment
• Chemical surface treatment
• Galvanic surface treatment

Bending Stiffness
Resistance of the needle to bending forces.

Bending Test
The bending properties are determined in a bending test. The needle shank is clamped. The point at which the force is applied is a specific distance from the clamping device (bending length). During the test the long groove is exposed to compressive stress, the short groove or clearance above eye is exposed to tensile stress (fig. 008). Readings are taken of the elastic limit, the force required to reach this limit, the breaking angle and the breaking force.

Blade

Part of the needle between the end of the shoulder and the top of the eye. We can distinguish between (fig. 009):

• Straight blade
• Supplementary shoulder
• Curved blade
• Tapered blade
• Reduced blade

Blade Cutting
Operation:
Cutting of swaged blades to the length required for die-pressing (fig. 010).

Blade Diameter
Diameter of the cylindrical section of the needle blade above the clearance above eye or the short groove, but not in the section of the reduced blade or supplementary shoulder (fig. 011).
Symbol: D
Unit: Millimeter (mm)

Blended Thread
see Core Yarn

Blind Hemming
Attaching facings, edges or hems on garments with a stitch that is barely visible on the outside of the garment.

Blind Stitch
Stitch that is barely visible on the outside of the garment (fig. 012). We can distinguish between single and multiple thread blind stitch machines.

Block Sewing Machine
Sewing machine with a block-shaped casting (fig. 013).

Blucold®
Trade name for a phosphated and then teflon coated needle surface. see PH-TE Needle.

Blueing of Surface
Intentional blue colouring of a non-nickel- or non-chromium-plated needle surface which is usually limited to just parts of the needle (i.e. threaded shank). A layer of metal oxide forms when the needle surface is heated. Depending on the thickness of the layer, different interference colours result. They change from yellow through brown, red, violet, and blue into grey. The thickness of the oxide layer depends on the intensity and the length of the heating.

Branding
Marking the shank of the sewing machine needle to identify the manufacturer and the needle size (fig. 014).

Breaking Angle
The angle reached when the needle breaks in the bending test.
Symbol: B
Unit: Degrees (°)

Breaking Force
The force needed to break a needle in a bending test.
Symbol: BK
Unit: Newton (N).

Breaking Load
see Ultimate Breaking Load

Buckling Strength
Resistance of a needle to buckling stresses. Every time the needle penetrates the fabric, it is under buckling stress. The section of the clearance above eye is the part in danger of breaking (fig. 015).

Bulged at Eye
Needle with the diameter of the eye section, one needle size larger than the nominal diameter.

Oversize bulged at eye: Needle with the diameter of the eye section, two needle sizes larger than the nominal diameter (fig. 016). When using these needles, the needle heating is supposedly lower than with needles which are not bulged at eye.

Bulked Yarn
see Textured Yarn

Bump
A special shape of the top of the eye on the side of a pontoon scarf (fig. 017). This is designed for a secure take-up of the loop by the hook/looper even under critical sewing conditions.

Butt
Flattened section at the end of the shank (fig. 018). For technical reasons the butt is not chromium plated.

Butt Grinding
Operation:
Grinding a flat section at the end of the shank. This section is called the butt (fig. 019).

Button Sewing Needle
Needles which are used in button sewing machines.

Button sewing needles usually have a short, extra heavy set tip (R-STU) point to largely avoid damage to the button and glide the needle into the hole in the button. Typical button sewing needles: 134-35 K, 175x1, 175x3, 175x7.

Butt to Top of Eye Distance
The distance between the butt and the top of the eye which is determined by the construction of the sewing machine and is of great importance for the stitch formation (fig. 020). Even if the needles have a curved blade, the distance is the straight length.
Symbol: 01
Unit: Millimeter (mm)

Calibrating
Operation:
The measuring and correcting of the radii of curved needles (fig. 021).

CAP
Abbreviation for Customer Applied Product. An existing needle system is slightly changed for a certain sewing application. Every variation has a number. After successful testing, the CAP needle has it's own system designation.

Centric Round Points
Needles with a point that is ground in a cone shape and with a tip positioned in line with the needle axis. The following types are centric round points:

Chamfer
Chamfered edge. The chamfering of an edge can be done by non-cutting or cutting shaping. The butt is a typical chamfer (fig. 022).

Chemical Deburring
Operation:
The needles are treated in a chemical solution considering the following influences:

• Time
• Temperature
• Concentration

Due to the special characteristics of the solution, the fins and other rough surfaces are smoothed.

Chromium Layer
Galvanically deposited chromium layer of high hardness and high wear resistance (fig. 023). The Vickers hardness number can go up to 12.000 N/mm2 depending on the plating conditions.

An advantage of the chromium layer, besides its high hardness, is its minimum growth of chromium oxide layers. A rapid growth does not start until 450 °C. This process already starts at 350 °C with Nickel, with iron or steel it even starts at 220 °C. During the sewing process these oxide layers worsen the friction conditions between the needle and the fabric. The thermical stress on the needle increases.

Chromium plated needles should be used when:
1. high thermical stresses (i.e. high sewing speed, several plies of fabric etc.) are involved.

2. a low coverability of the needle surface is required, i.e. with melting or finishing particles (sewing of synthetic or blended fabrics, or strongly finished materials. see Oxide Layer Growth

Chromium Plating
Operation:
Direct galvanic deposit of a hard chromium layer on the needle surface (fig. 024).

Clamping Length
1. That part of the needle shank which is put into the needle bar.
2. That part of the shank which is placed in the clamp during a bending test (fig. 025).
Symbol: EL
Unit: Millimeter (mm)

Cleaning
Operation:
Cleaning the needles of processing oils, grinding dust, polishing pastes, quenching oil etc.

Clearance above Eye
Depression in the needle allowing an unhampered motion of parts of the machine below and above the throat plate. There are clearances in the blade (fig. 026-1) and directly above the eye.

1. Pontoon Clearance above Eye (fig. 026-2) Clearance above eye of which the bottom is parallel to the needle axis.
Advantage: Easier adjustment of the position of the hook to the needle. Higher precision when the hook picks up the loop.
Disadvantage: Lower loading capacity (buckling and bending) due to smaller cross section of needle.

2. Radius Clearance above Eye (fig. 026-3) Clearance above eye with a curved run. With constant diameter of blade and increasing needle size, the distance between the needle and hook decreases.

In order not to have to adjust the hook every time the needle size is changed, a depression is ground above the eye. The radius of the depression equals that of the grinding stone used. Today this type of clearance above eye is die pressed.

Advantage: A needle with a radius clearance above eye is more resistant to mechanical stress (buckling and bending) than a pontoon clearance above eye.

Clearance above Eye Depth
Distance between the deepest point of the clearance above eye and the highest point of the eye at the end of the clearance above eye (fig. 027).
Unit: Millimeter (mm)

Compound Polishing
Operation:
The needles are put in a drum set at an angle together with polishing chips, a chemical compound and moved in water. As the drum rotates, the chips and needles rub against each other in the fluid and the edges and the surfaces are smoothed (fig. 028).

Continuous Filament
see Filaments

Continuous Thread
see Filaments

Cooling Groove
Long groove which extends into the shank. The width of the cooling groove is the same as the long groove. The bottoms of the long groove and the cooling groove are level. Needles with cooling grooves are used on specially equipped sewing machines. The needle bar on these machines is hollow. Thus the effect of an air-pump is reached during the up and down movement of the bar. The sucking in and blowing out takes place along the long groove.

However, the reduction of temperature reached by the airflow is relatively small. The reason is that the section which is heated most (i.e. the section just above the eye) is not reached by the airflow efficiently enough (fig. 029).
see Needle Heating, Needle Cooling.

Cool Needle
Trade name for a needle with a cooling groove.
see Cooling Groove

Copper-Beryllium Needle
Sewing machine needle made of copper-beryllium wire.
After special heat treatment the needle has bending properties which are required for a specific sewing process and which result from this copper alloy. These needles are used to sew gun-powder sacks because this material more or less stops the formation of sparks.

Cord Embroidery
Cords are applied with a special attachment on a multi-head embroidery machine. A special needle system was developed —DBxK 5 KK which has a short shank. This avoids the unwanted widening of the stitch even when the cord is thicker.

Core Thread
Core threads consist of several filament core fibres which are surrounded by spun staple yarns. We can distinguish between polyester cores

• spun by cotton (most frequently used)
• spun by polyester staple fibre

In the case of a polyester/cotton core yarn, the polyester filament provides the necessary breaking load while the surrounding cotton yarn protects the polyester filiament from high temperatures (needle temperature, ironing temperature) When sewing, the shift of twist of a core thread is less (advantage when zigzagging or stitching backwards).

Corrosion
Reaction of a metallic object with it's surroundings. The corrosive product of a sewing machine needle is rust. Rust needs water as a reaction partner. The water can be in a liquid or gaseous state (vapour). Our needles are treated in a special way after being nickel or chromium plated. Also specially treated paper is put into the needle packaging. Thus the rust protection is increased even by high air humidity and high outside temperatures.

Covering Chain Stitch
The needle threads are locked with a cover thread on the top and a looper thread underneath the fabric. This stitch type is used to cover the top or bottom of a seam (elastic material).
The covering chain stitch is assigned class 600, e.g.
602 two needle threads, one looper thread, one top cover thread.
605 three needle threads, one looper thread, one top cover thread (fig. 030).
607 four needle threads, one looper thread, one top cover thread.

Cross Point
Construction:
The cross point is ground in a wedge shape at right angles to the threading direction.
Symbol:
S or CR
Stitch hole:
The sewing material is cut at right angles to the threading direction; it is widened by the blade.
Seam apperance:
The seam is straight and pulled in very strongly (fig. 031).
Retained strength:
The loss of strength caused by the cross point is only exceeded by the square and triangular points.
Application:
The cross point is used where straight and well set seams are required. You have to be careful about the amount of stitches per cm. Remember!! Needles with a wedge point have to be used to obtain the cutting effect of the cross point when the sewing machine has a cross positioned hook or looper.

Cross Stitching Width
Distance between 2 successive stitches across the direction of the seam. Unit: Millimeter (mm), inch.

Curved Needles
Needles with blades (and in some cases also the shanks) which are curved to a specific radius.
Typical needle systems

• Blind stitch sewing machines:
  1669 E, 1669 EU, 251, 251 LG, 251 EU, 1717
• Overedging machines:
  60 M, UY 154, UY 8484

The curved blade of the needle

• Helps the take-up of the needle thread 1 by the looper 2 (fig. 032)
• Enables the joining of fabric plies 1 without a visible seam on the face of the fabric-blind stitching (fig. 033)

Cutting
Operation step:
Dividing the needle blanks from the remaining material by using cutting tools in the Integrated Technology.

Cutting point Grinding
Operation:
Grinding needle points with cutting edges

Cutting Points
Sewing machine needles with cutting points are predominantly used for sewing leather. A specific seam appearance is achieved by a specially ground shape. At the same time the cutting point reduces the resistance of the sewing material. There is a great variety of points.

The necessity of which, though, is very controversal. Tests have proven that any seam appearance can be obtained with only six different types of cutting points.They are:

Any other cutting points can be regarded as derivatives of these six basic types. In the needle catalogue the derivative points are only shown with their contours. Based on retained strength (strength of the leather after stitching), cowhide has the lowest and calf leather the highest loss of strength. Kid leather ranges in the middle. The loss of strength depending on the cutting effect lists as follows (fig. 034):
   Wedge point (lowest loss of strength)
   Twist and reverse twist points
   Cross point
   Square point
   Triangular point (highest loss of strength)

Considering the needle heating resulting from the cutting effect, the points list as follows (fig. 035):
   Wedge point
   Square point
   Twist and reverse twist point
   Cross point
   Triangular point

Basically, any requirements of the leather industry concerning the seam appearance can be met by these six cutting point types.

Damage of Fabric Yarn
Damage of individual fabric yarns by the sewing machine needle, mainly in densely woven fabrics.
Solutions:
use the smallest possible needle size
use needles with a light ball point (R-SES)
use of thread lubrication
slight dabbing of the fabric with lubricant before sewing.

Decorative Stitching
Seam which is designed to decorate a garment. The visual effect of the seam is influenced by:

• stitch type
• stitch length
• stitch width
• colour and size of the thread
• shape of point (leather)
• sewing machines with attachments to make special stitches (braided, honeycomb)

The decorative seam can at the same time be an attaching seam (e.g. stitching edges, hems, pockets, appliques).

Deep Cooling
Operation:
Treatment of the hardened needles at temperatures of about -100 °C. Deep cooling results in structural changes. Together with a coordinated tempering process this consequently results in a high elastic limit.

Die-Pressing
1. Divided Technology
Operation: The creation of the eye section (point groove, clearance above eye or short groove , shaping of the eye) by pressing the swaged needle blades with pressing dies (fig. 036).

2. Integrated Technology Operation step:
The creation of the eye section, the long groove(s) and the needle blade by pressing the wire blank with pressing dies (fig. 037).

DIN
see German Industry Standard

Divided Technology
Technology used for the production of sewing machine needles where there is a very detailed division of working operations. This type of technology goes back to the origins of the sewing machine needle. In over 100 years, the only things that have changed are the production speed, precision of the machines and the life of the tools. However the percentage of labour costs could not be decisively reduced.
The divided technology is still the world-wide used way to manufacture sewing machine needles. Obviously, countries with low labour costs have a considerable advantage. Therefore it is of no surprise that China has the most sewing machine needle factories and produces the most needles. We are the only sewing machine manufacturer in the world that has gone another way. The Integrated Technology that was developed by our company integrates the working operations that are necessary to produce the basic needle in just one piece of equipment.
See Needle Manufacturing, Integrated Technology

Domestic Sewing Machine Needles
Sewing machine needles which are used in domestic sewing machines. Their distance butt to top of eye is usually 33.9 mm and the shank diameter is 2.04 mm. Depending on the needle size, the shank is flattened to different degrees on the side of the clearance above eye (short groove). This ensures an exact positioning of the needle to the hook of the sewing machine (fig. 038). No other sewing machine needle system is manufactured in the quantities like the domestic sewing machine needle (Systems 130/705 H, 15x1 H, 15x1/705 H, 206x15, HAx1, PFx130)

Double Chain Stitch
One or several needle threads are interlocked with one or several looper threads.
The double chain stitch class 400 includes:
401 double chain stitch, one needle, straight stitch (fig. 039)
402 double chain stitch, two needle, straight stitch
404 double chain stitch, one needle, zigzag The special characteristic of this stitch is the inlerlocking of stitches on the reverse of the fabric.

Double-eyed Needle
Needle with 2 eyes. One distance from the butt to the top of the eye is 31,9 mm, the other 33,9 mm. This needle can only be used in domestic sewing machines with a cross positioned hook. Threading of the second eye (01 = 33,9 mm) results in a perfect zigzag stitch. Threading the first eye 01 = 31,9 mm) results in skip stitches in the right or left seam depending on the type of hook, thus the length of the stitch is doubled. This stitch is used for decoration or basting (fig. 040).
The modern domestic sewing machines have made this needle redundant.

Double Groove Needle
These needles have a second long groove on the side facing the hook. It usually runs from the end of the shoulder to the "land" or the beginning of the eye (fig. 041). The second groove is usually not as deep as the first long groove.

Double Lock Stitch
The double lock stitch is class 300. It is done by interlocking 2 threads. The needle pushes the thread through the fabric forming a loop. A quantity of the lower thread is pulled through this loop. The stitch is locked in the centre of the fabric (fig. 042).

Double Pointed Needle
This needle has two pointed ends with the eye in the middle. Each end has a clearance above eye and these are designed to guide and secure the needle in the needle bars (fig. 043).
Systems: 1032 B1; 2000 A; CTA-2352 A

Eccentricity of Point
Deviation of the tip from the needle axis.

Eccentric Points
Needle points of which the tip is purposely located outside the needle axis. The position of the tip depends on the threading direction and is stated in degrees. To determine the position of the tip, the needle is placed vertically on its point, the threading direction must be from left to right and starting from the threading direction anti-clockwise (fig. 044).

Ecological Needle Production
The energy used and the amount of enviromental pollution is considerably less than the conventional technology used for manufacturing sewing machine needles. The basis for the ecology balance is 200 Million sewing machine needles produced in the Integrated Technology compared with the same quantity manufactured in the world-wide conventional divided technology. The balance shows the convincing superiority of the Integrated Technology. The larger amount of steel waste as well as hard metals is re-cycled (fig. 045).

Elastic Fabrics Sewability
see Foundation Garments Sewability

Elastic Limit
The angle at which the needle does not completely return to it's initial position upon release of a load in a bending test (beginning of plastic deformation). Symbol: EG Unit: Degrees (°)

Embroidering
Producing abstract or figurative motives on a backing (textiles, leather etc.) with a needle and thread either manually or on a machine. The type of embroidering dependings on the following:

• type of stitch (cross, flat, knot, knit, lock, chain, loop)
• production method (hole, perforation, lace)
• backing or thread (linen, silk, gold)

Embroidery Machine
A machine for sewing abstract or figurative motives on a backing (textiles, leather etc.) There are semi and fully mechanical embroidery machines.

Hand embroidery machine
This works with a two pointed needle with the eye in the middle and a thread. The motive is made on a pantograph which is moved manually.

Shuttle embroidery machine
This machine uses the double lock stitch method with a normal sewing machine needle. The bottom thread is wound on a bobbin which is put in a shuttle which is used as the hook. The movement of the backing material is controlled either by punch cards, belts or computer discs.

Crank embroidery machine
A chain stitch is produced with a hook needle and a thread. The backing is moved by means of the crank.

Single or Multi-head embroidery machines
The machine produces a double lockstitch with a normal sewing machine needle and a hook with thread. The backing material is clamped in a border or single frame. The movement of this frame is controlled by punch cards, belts or computer discs.The embroidery head can be fitted with several needles (multi-coloured embroidery). There are special attachments for applying cords or sequins or for making holes. The amount of heads determines the amount of identical motives that are embroidered simultaneously.

Embroidery Machine Needles
Needles which are used on embroidery machines.
E.g. systems
   854 S Shuttle embroidery machine
   253 C Crank embroidery machine
   DBxK 5 Single or multi-head embroidery machines
Extreme stress situations can occur on single and multi-head embroidery machines caused by the following:

• the abrupt movement of the fabric in the frame
• large transport distances
• extraordinary high friction forces on the thread due to

• Large cross-stitching widths
• Continuing movement of the upper-thread whilst the needle is not in operation use of metallic threads
• Intentional use of different sized threads

We developed in coordination with the practical field a special embroidery needle-DBxK 5. Especially the shape of the groove edges considerably improves the friction conditions of the thread. A wide long groove protects the special embroidery threads from excessive friction with the fabric. The large eye creates less problems when using bulky thread. The optimal point means more safety when embroidering thick material at high transport speeds.
When sewing on cords, you can use the system DBxK 5 with a short shank —DBxK 5 KK.
The short shank avoids an unnecessary widening of the stitchhole even if the cord is thicker.

Embroidery Needle
A tool for manually decorating textiles with stitches. The size and length of the needle depends on the material, thread and the type of embroidering. Needles with a blunt point (stramine needles 1) are used for coarse and those with a sharp point (2) are used for fine material (fig. 046). These needles have a large eye.

Embroidery Thread
Used either on a machine or manually. The embroidery threads mainly have a visual function. The ultimate breaking load of an embroidery thread is most of the time lower than that of a sewing thread. Viscose threads (rayon) are mainly used because of their shiny appearance. Also metal or metalized synthetic or wool threads are used.

Extra
Needle systems with this additional designation have a fixed breaking point. See Fixed Breaking Point

Extra Heavy Set Point
Construction:
The extra heavy set point starts to taper to a pointed cone just above the eye. The tip is ground at an obtuse angle (fig. 047).
Symbol: R-STU
Application: The extra heavy set point was specially designed for button sewing machines. Certain systems just have this one point, e.g. 1984, 1985, 1986, 2018, 108x1, 175x1, 175x3, 175x7

Eye
An exact opening in the needle blade through which the thread is inserted. The top and end of the eye must be well rounded and free of fins as well as the sides. The most frequently used shape of eye is a rectangle of which the narrow sides are shaptcl in a semi-circle. The width of the eye (03) usually equals 40% of the blade diameter. Eyes which are less than 40% are called "small eyes"(EO), eyes which are over 40% are called "wide eyes". (E.g. small eye — system 1000 E0, wide eye — system B 27 B).

The length of the eye (02) is the distance between the top of the eye and it's end (fig. 048). If the diameter of the blade increases, the length also increases (exceptions are some needles for blindstitch machines). Typical needles for Singer sewing machines have a slightly shorter eye. The difference in length between Singer needles and needles of other brands depends on the size of the needle (e.g. Nm 80 = 0.09 mm, Nm 160 = 0.20 mm).
The eyes of some sewing machine needles are constructed a little longer (e.g. system 1065 K, 110 S). The longer eyes allow sewing with threads that have knots and also enable threading during embroidering on multi-head machines. see Long Eye

Eye-pointed Needle
Needle that has it's eye at the point. This construction was the basic requirement for the rapid development of the sewing machine. The first to ever use this needle was Balthasar Krems in 1800. see Needle History

Eye Polishing
Operation:
The smoothing and rounding of the sharp and roughtedges which result from punching the needle eye. Each needle is threaded individually on a thread coated with polishing paste, clamped into a machine and moved so that each edge and rough spot is smoothed.

Feeding Device
Mechanism on a sewing machine which moves the fabric by a certain amount (stitch length). The feeding motion can be intermittent or continuous. The feeding can be performed by

• a drop feed
• a top feed
• a needle feed
• a unison feed (combination of 2 or all 3 types)

Feed off-the-arm Machine
Special industrial sewing machine. The arm of this machine is bent in a L-shape, the shorter side is slanted to the bottom. This machine is used for closing side seams and sleeves (especially on workwear and underwear) (fig. 049).
Fibula
A needle discovered about 1400 BC which could securely join two parts of a garment but which could be loosened very easily (fig. 050). Also called a clasp or slide. see Needle History, Safety Pin
Filaments
Yarns consisting of several single, continuous fibres which are twisted.

Fin
Surplus material resulting from die-pressing the eye section. Also sharp edges formed during pressing, milling, punching or grinding.
see Fin grinding

Final Grinding Cutting Point Needles
Operation:
The finishing of the point of a cutting point needle in a hard condition by manual grinding.
see Pre-Grinding Cutting Point Needles

Fin Grinding
Operation:
Removal of the fin resulting from die-pressing the eye section (fig. 051 conventional technology) or after cutting (fig. 052 Integrated technology)

Fin Pressing
Operation step:
Reducing the thickness of the fin produced when pressing the complete needle in the Integrated Technology press.

Flatbed Sewing Machine
Sewing machine with a flat base plate (fig. 053). The base plate and the surface of the machinetable are usually level. This type of construction is the most frequently used.

Flattened Shank
Needle shank with one or two flat surfaces. These are arranged at a specific angle to the threading direction depending on the type of sewing machine (fig. 054).
The purposes of the flattened shank can be:
1. Proper positioning of the needle to the point of the hook (e.g.domestic sewing machine needles 130/705 H).
2. The flattening determines the spacing between needles.

Certain needle systems (e.g. 950, MY 1072) are only flattened to a certain length. This partial flattening allows an unhampered movement of machine parts above the throat plate.
see Flattening, Parallelism of Flattened Shank, Thickness of Flattened Shank

Flattening
Operation:
Flattening one or two sections on the shank. This can be done by grinding, milling or pressing (fig. 055)
see Parallelism of Flattened Shank, Flattened Shank, Thickness of Flattened Shank, Flattening of Shoulder.

Flattening of Shoulder
Operation:
Flattening one or two parts of the shoulder. This can be done by grinding or milling. This flattening ensures the necessary distance between shoulder and presser foot or other machine parts (fig. 056).

Flexibility
An undefined term for the elastic characteristics of a sewing machine needle. The word elasticity is better. see Elastic Limit

Flutter
Oscillating motion of the needle during sewing mainly occurring when using small size needles with a long blade. The reasons can be:

• Deflection of the needle by yarns of woven or knitted fabrics.
• High thread tension
• The fabric is moved although the needle has not yet emerged from the fabric (except sewing machines with needle feed)
Possible solutions:

• Use needles with supplementary shoulder.
• Use a thicker needle if possible.
• If possible use a sewing machine class that takes a shorter needle.
• Lower the thread tension
• Adjust the sewing machine.

Forte
Suffix for needle systems which have a blade diameter one needle size larger than the stated needle size. The size of the eye, long groove and relief grinding however correspond to the stated size.

Foundation
Wear Sewability When sewing foundation wear, the needle can damage or cut the mostly elastic fibres. This can lead to a loss in the quality (fig. 057).

Possible ways of avoiding this are:

• use the smallest needle size possible
• use needles with a ball point. The coarser the fabric, the larger the ball point should be. R-SES, R-SUK, R-SKF.
• use a needle with the special point R-SKL when sewing fabric made from non-spun Elasthan fibres.
• dab the fabric around the area to be sewn with a thread lubricant. This reduces the friction between the fibres of the foundation wear and the needle can push the fibres aside easier.

Free Arm Sewing Machine
See Arm Bed Sewing Machine

Fur Needle
Needle which is predominantly used on fur sewing machines (e.g. systems 292 SP, 459 R)

Galvanic Treatment
See Chromium Plating, Nickel Plating, Nickel

Garment Pin
A type of pin used for centuries to join, fix or just as jewellery on garments. There is a head (1), blade (2), point (3) and neck (4) (fig. 058).
see Fibula, Safety Pin

German Industry Standard
There are three standards in use for sewing machine needles
DIN ISO 8239: Dimensions of sewing machine needles
DIN 5325: Needle size comparisons
DIN 5330 Part 1: Terms, symbols

Glove Needle
Needles that are used for sewing gloves on machines. The size of the blade of these needles is relatively small (Nm 50-90). Typical system is 573 N.

Groove
Furrow like depression.There are :

• Long grooves
• Short grooves
• Double grooves
• Three grooves
• Spiral grooves
• Spiral shaped point groove
• Cooling groove

The grooves are either milled or die-pressed.

Grooved Shank
U-shaped depression along the entire length of the shank. The size of the shank groove is constant (fig. 059). A pin in the borehole in of the needle bar fits into the grooved shank and thus ensures an exact positioning of the needle.

Groove Twisting
see Needle Blade Twisting

Handicap Needle
see Threading Aids

Hard Chromium
see Chromium

Hardening
Operation:
Heating the needle to a temperature of at least 800 °C. Temporary exposure to this temperature and quenching in oil (fi. 060).

Hardening Distortion
Unintentional change in the shape of the needle after the heat treatment. It is caused by an unbalanced distribution of heat and/or transformation stresses. The hardening distortion depends on the geometry of the needle (cross section), the hardening conditions and the wire.

Hardness
Hardness is defined as the resistance of a material to the penetration of an other, even harder material. The hardness of a sewing machine needle is tested by the Vickers method. A diamond pyramid is pressed into the polished section of the needle to be tested. The load can be 10, 30, 50 or 100 N. The square surface area of penetration is then measured. The deeper the diamond

pyramid is pressed into the material, the larger the surface area gets and the lower the hardness of the needle.
Unit: N/mm²
Symbol: e.g. HV 30
HV = Vickers hardness number
30 = test load in Newton
There is no direct relationship between the hardness of the needle and it's bending properties. Inferior hardness does not necessarily result in a large breaking angle. On the other hand, a high Vickers hardness is not the reason for an inferior breaking angle. In both cases, the notch effect has a considerable influence on the bending properties of the needle.

Hard Straightening
Operation:
The elimination of the hardening distortion by hammering the needles (fig. 061).

Heat Treatment
Operation:
Proceedures composed of specific temperature-time-sequences that result in optimum bending characteristics. These comprise hardening (he-ating and quenching), deep cooling and tempering.

Hook
Part of the sewing machine. It is designed to interlock the loop made by the needle with itself or with one or more other lower threads.

Hook Needle
Needle which has a hook instead of an eye (fig. 062).

Hook Protection
This is the assumption that the formation of a loop at the short groove or clearance above eye is helped by a staggered positioning of the top and the end of the eye. Thus creating larger space between the needle and the hook or looper (protection of the hook from touching the needle). During the needles upward motion from the lower dead centre, the needle forms loops of equal size on both sides of the needle. Especially alterations to the hook shift the loop from the side of the long groove to the side facing the hook. This is the only way to increase the certainty of the hook or looper picking up the loop (fig. 063).

Inhibition
Treatment of sewing machine needles with substances which hinder or reduce chemical or electro-chemical processes. This is initially to stop corrosion of the sewing machine needles after certain operations.

Integrated Technology
The unique technology for manufacturing sewing machine needles which was developed by our company and introduced in 1987. This technology took over the conventional technology used for over 100 years.
The wire is cut to a length of 2 needle blanks on the straightening and cutting machine.These needle blanks are cleaned and then rounded on both ends. After being cleaned again and dried, they enter the press on 2 symetrically running spindles. 8 easy exchangeable modules are installed in the column mount of the press. These modules contain the tooling. The spindles transport the blanks past each single module. The blanks are moved from module to module and treated in a different way with each stroke of the press.

The last module cuts and divides the needle blanks. Each stroke means 2 needle blanks. 600 blanks can be produced per minute. The blanks leaving the press have all the geometrical characteristics of a sewing machine needle except for the point which is made on a special machine (fig. 064).

Jeans Needle
Domestic sewing machine needle which is especially designed for sewing denim. The jeans needle has a slim point (R-SPI) and is chromium plated.

Kevlar®
A Para-Aramid fibre with a high specific ultimate breaking load, small elongation and an excellent resistance to heat (no melting and a decomposition temperature of 500 °C). Kevlar® is also spun into a sewing thread which is used for sewing heat and fire proof garments or in the leather industry where the thread is subject to extensive thermical stress. The ultimate breaking load of Kevlar® is 5 times higher than steel and is 30% higher than Nomex It is difficult to dye the fibers. Kevlar® is relatively sensitive to ultra-violet waves which leads to a loss of the ultimate breaking load (up to 50% depending 6n the length of exposure). Kevlar® DuPont's registered Trademark.

Klenkes
An Aachen dialect description for the small finger which is used during the visual inspection of sewing machine needles. The faulty needles are "ejected" by the "Klenkes".
The "Klenkes" has become a gesture of the people of Aachen. The right hand with the palm facing the body is made into a fist with the little finger straight and held up at least head high. If "Aachener" meet, especially somewhere foreign, then this gesture shows their attachment to Aachen. It was no wonder that the people of Aachen wanted to see this gesture immortalized. The sculptor, Hubert LOneke, was given the task and the bronze stature was unveiled on the Holzgraben in the centre of Aachen on 9th October 1972 (fig. 065).

Knitted Goods Sewability
When sewing knitted goods mesh loops can be destroyed by the needle.
The destruction of mesh loops in goods made of natural fibres is mainly due to mechanical influences, in goods of man-made or blended fibres, it is mainly due to mechanical and/or thermical influences. The destruction of mesh loops by mechanical influences depends directly on the construction of the fabric. The four binding points (plain knitting) are most likely to be damaged. If the needle hits such a binding point, a relatively large amount of yarn has to be pulled from the neighbouring mesh loops to widen this one loop. If the friction between the yarns is too high, this is impossible. This tension at the binding point increases rapidly and the mesh loop is destroyed (fig. 066).
To avoid destruction of the mesh loop you should remember the following:

• Do not use damaged needles (e.g. damaged point) t Check feed dog, throat plate and presser foot for rough edges
• Needle size as small as possible
• Use needles with a ball point. The chances of stitching into these binding points is reduced with a ball point.
• Good aids are thread lubricants which can be sprayed on the fabric in small amounts reducing the friction between the fibres

themselves and between the fibres and the penetrating needle. Mechanical and thermical mesh loop destruction can be effectively avoided.
• Mesh loop destruction is minimized or may even be completely avoided when the fabric is especially treated. The friction of the loop yarn is much lower when the fabric has been treated. The widening of the loop by the needle causes less problems. Needle heating is low. Thermical destruction does not occur.

Kooltorr
see PPK-Layer

Label Count
see Thread Count

Land
A "land" is only found on double groove needles with a short groove or clearance above eye. It is the part which separates the second long groove and the short groove or clearance above eye (fig. 067)

Leather Needle
see Cutting Points

Leather Points
see Cutting Points

LL Point
see Twist Point

Long Eye
Long eyes are mainly in needles for embroidery machines (fig. 068). Advantages:

• use of threads even with large knots
• threading during the embroidery process
• use of bulky threads.

Long Groove
The long groove runs from the end of the shank to the top of the eye. It always faces the threading direction and is usually the same width as the eye (40% of the blade diameter) (fig. 069). All sewing machine needles (except Hook and double point needles) have a long groove. It is designed to protect the needle thread against high friction between the fabric during the penetration of the fabric and also when widening the loop.

Looper
see Hook

Loop Taking Stroke
Distance which the sewing machine needle covers from the lower dead centre until the point ot hook takes up the loop formed by the needle. For domestic, artesan and industrial sewing machines, it can range from 1.6 to 2.8 mm, for shoe or saddler sewing machines it may be as high as 5 mm.

LR Point
see Reverse Twist Point

Magicol
see PH-TE Needle

Maguey Needle
An extraordinary, natural needle with thread produced from the Agave americana. The agave americana belongs to the Amaryllis genus from Mexico. The large, rosette-shaped, fleshy, grey-green leaves have a sharp dark brown point. These leaves can be 3 metres long and have very strong fibres (pita fibres) which run along the length of the leaf (fig. 070).

Mechanical Stress of the Needle
During the sewing process the needle is stressed by forces acting in two different directions.
1. Forces that cause a deflection of the needle from it's proper stitching direction (fig. 071).
2. Forces that counteract the needle's penetration of the fabric.
In the first case, the needle is subjected to bending stresses, in the second it is subjected to buckling stresses.
A deflection of the needle from it's correct stitching direction can be caused by

• inhomogeneousness of the fabric (e.g lumps)
• sewing over cross-seams or pins
• high thread tension

• pulling the fabric manually while stitching
• removing the fabric from the machine without loosening the needle thread tension

The degree of deflection may be influenced by:

• needle size
• length of the needle
• amount and shape of the grooves
• shape of blade (supplementary shoulder, reduced shoulder)
• length of the shank
• heat treatment

The buckling stress resulting from the resistance of the fabric is usually compensated by the sewing machine needle quite easily. A deflection of the needle from it's stitching direction almost always precedes the final breakage of the needle. The needle either hits the presser foot, the throat plate or even the hook/looper. In most of the cases, it is a combination of bending and buckling stresses that cause the needle to break.

Micro-fibre Fabric Sewability
Fabrics made out of Micro-fibres are produced in different weaves and with different finishes. The amount of warp and weft threads per cm is relatively high. The threads are made out of single fibres with a fineness of 0.5 dtex and lower. 0.5 dtex = 10.000 metres of the single fibres weigh 0.5 gm or if the single fibre was wrapped around the globe, it would be 40.000 km long and only weigh 2 kg. This very close weave of the fabric leads to displacement puckering which can be reduced if :

• The smallest needle size possible is used
• A double chain stitch is used(no interlocking of the stitch in the middle of the fabric)
• The seam is not parallel to a warp or weft thread
• The stitch density is low (3.5 to max. 4 stitches per cm)

Other points should be noted when sewing a micro-fibre fabric:

Milling
Operation:
Making the grooves (fig. 072 long groove 1 and second long groove 2) with a disc cutter. The size is approx. 40% of the blade's thickness.

Monofilament
Thread made from a single clear filament which is extruded through a one-hole spinneret. Its prime purpose is to provide an optimum colour matching of the thread and the fabric and to thus minimize the demand of coloured threads.
Further advantages:

• Total evenness of the thread
• High breaking load
• Low thread size (high length of bobbin thread on double lock stitch)
• No shifting of twist

Disadvantages:

• Low heat resistance
• Not supple
• Thread ends "prick"

Multilabelling
Label for packing strip.
The label provides information about:

• The amount of needles in the packing strip
• Special types of points
• The main parallel systems
• The metric needle size, the corresponding Singer size and, if necessary, the equivalent system size.

E.g.	10      R-SES
	UY 128 GAS; 1280;
	MY 1040; MY 1044;
	DVxG 9;
	UYx128 GAS
	100 / 16 / 040

see Packing Strip



Needle Bar
Mainly cylindrical, tube-like part of the sewing machine (fig. 073).
A clamp is slid over the lower end of the needle bar. A screw presses the needle shank into the slot of the needle bar. In the case of many machines, the needle shank is simply placed into the borehole of the needle bar and is clamped by a screw situated on the side.
The length of the slot or the borehole or a pin which is positioned at right angles to the borehole or slot determine how far the needle is inserted.
The needle clamp or the bottom end of the needle bar often serve as the last thread guide before the needle eye.

Needle Blade Twisting
Operation:
Internation twisting of the milled needle blade to obtain a spiral-shaped run of the long groove(s).
see Grove Twisting

Needle Breakage
Destruction of the needle by excessive buckling and/or bending stresses during sewing. Possible causes of needle breakage and ways to eliminate them are:

• Replace bent or damaged needles
• Use correct needle system for the machine class
• Check exact positioning of the hook, feed dog, loop taking position
• Correct cutout of presser foot and throat plate
• Stitch over cross seams slowly
• Check the relationship of the needle size to thread count
• Avoid extreme needle heating
• Avoid too high thread tension
• Use quality thread
• Avoid sewing across pins

Needle Cooling
Loss of heat which is generated by the friction between the needle and the fabric. The heat is dissipated by the thread as soon as a needle temperature of approx. 130 °C is reached. Thread lubrication effectively assists this process.
Most of the suggestions for needle cooling try to expose the needle to a direct airflow, continuously or intermittently, during sewing. There is no doubt about it's efficiency if the airflow hits the needle in the eye section. But, in the most cases, this cannot be guaranteed especially when the air nozzle hampers the view or handling of the fabric. In addition, the airflow can bother the operator. The same is true with intermittent spraying of a mixture of air and oil. A perfect needle cooling system does not yet exist.
see Cooling Groove, Needle Heating, PH-TE Needle, Ni-PTFE, Thermical Stress of the Needle

Needle Distance
1. The distance between two or more needles in a multi-needle sewing machine. It is measured between the needle axes (fig. 075).
2. Distance between the two blades of a twin needle.
Unit: Millimeter (mm), Inch

Needle Feed
Sewing machines in which the needle bar performs a feeding motion while the needle is still in the fabric. This motion is synchronized with the drop feed motion.

Needle Heating
The rise in temperature of the sewing machine needle caused by friction with the fabric during penetration and emerging and/or by friction of the thread passing through the eye. If the friction of the fabric is low, the heating of the needle is predominately caused by the thread passing through the eye. (Friction of the thread with the edges of the eye). The limit is a needle temperature of approx. 130 °C. When this limit is exceeded, the thread distributes the heat, i.e. the maximum needle temperature is lower when sewing with thread than without.

Needle heating depends on:

• Fabric (kind of fibre, weave, knitted goods, finish, number of plies, fabric combinations)
• Sewing machine (speed, stitch type)
• Thread (kind of fibre, finish, construction)
• Needle (size, surface, point, shape)
• Environment conditions (humidity)
Under certain conditions the maximum temperature of the needle can reach 450 °C. This tempering effect (reduction in hardness, loss of elasticity) can quickly lead to a worthless needle.
The highest needle temperature is usually measured at the eye (exceptions are needles with a conical blade, supplementary shoulder or when sewing a large amount of plies) (fig. 076). There is a analogy between the distribution of heat along the needle and the penetration force. The highest temperatures are measured on that part of the needle with the highest penetration force.
Possible solutions to.over-heating are:
• Thread lubrication
• Dabbing or spraying the fabric with a lubricant
• Blowing air or air/silicone mixture against the needle
• Reduction in sewing speed.
  see Thread Lubrication, Cooling Groove, Needle Cooling, PH-TENeedle, Thermical Stress of the Needle

Needle Inspection
see Production Inspection, Visual Inspection, Product Inspection

Needle Manufacturing
There are a numerous amount of operations necessary before a sewing machine needle is finished and packed.
There is a difference in the treatment in a soft condition depending on whether the semi-finished needles were manufactured in the conventional way or with the Integrated Technology.
1. Main Operations
  1.1 Treatment in a soft condition
    1.1.1 Conventional Technology
          Wire straightening and cutting
          Swaging
          Cutting, rounding, butt-grinding, straightening and branding
          Die-Pressing
          Groove milling
          Fin grinding
          Pointing
    1.1.2 Integrated Technology
          Wire straightening and cutting
          Rounding
          Pressing
          Fin grinding
          Pointing
  1.2 Treatment in a hard condition
      Heat treatment
      Chemical deburring
      Straightening
      Polishing Chromium plating
      Packing
2. Special Operations
These are operations for specific needle systems
Needle blade twising
Point bending
Pre-grinding of cutting points
Flattened point grinding
Bending
Shank notching
Threading for eye polishing
Eye polishing
Drumming
Final grinding of cutting points
Point polishing
Flattening
Calibrating

3. Intermediate Operations Cleaning (after certain operations such as swaging, milling)
Sorting (for all manual operations or where machines are filled manually)
Weighing (after every operation. Calculation of production losses)

4. Additional Operations Manufacturing of tooling.
Swaging dies, branding dies, die-pressing tools, punches, eye punching dies, eye smoothing dies, pressing dies, cutting dies,

5. Inspection
Receiving inspection
Production inspection
Visual inspection
Product inspection

Needle Protection
Device on the sewing machine which prevents the needle touching the point of the hook during the take-up of the loop (fig. 077).

Needle Size
The needle size is the diameter of the needle blade just above the clearance above eye or short groove. The needle size is shown on the shank of the needle.
The metric size (Nm) equals the diameter of the cylindrical needle blade multiplied by 100. E.g. 0.80 mm x 100 = Nm 80. The diameters of the reduced or supplementary blades or above the eye are not really suitable for determining the needle size (fig. 078).

Besides the metric needle size there are about another 34 sizing systems which indicate the needle size

Needle System
The needle system describes the needle which belongs to a certain sewing machine class. This consists of numbers, letters or a combination of both. In our catalogue and other publications showing lists of needles, the needle systems are listed as follows:
  1 General Systems
  2 Singer (X)
  3 Singer (SY)
  4 Union Special
  5 Mauser
  6 Rimoldi
  7 Merrow
  8 Bonis
  9 Reece
  10 Japan
  11 Domestic

Needle Temperature
see Needle Heating

Needle Thread
Thread which is threaded in the sewing machine needle and is guided by this needle.

Needle Wire
Original material for sewing machine needles.
Special requirements:

• Low tolerances of the wire diameter (nominal size -0.01 mm)
• No decarburization
• No surface oxidization
• Specific size of ferrite grain
• Specific amount of cementite per pm
• Chemical analysis

Nickel
Sewing machine needles are nickel plated as long as the thermical stress is low during sewing (the majority of domestic sewing machine needles). The nickel is deposited galvanically and directly on the needle surface.
Nickel has the chemical abbreviation Ni.

Nickel Peeling
Peeling of the nickel layer caused by mechanical stress (bending, buckling, friction) (fig. 079).

Possible causes:

• layer is too thick
• incorrect treatment of the needle surface before nickel plating (layer of oxide or grease)

Nickel Plating
Operation:
Direct galvanic deposit of a nickel layer on the needle surface.

As nickel has a relatively low resistance to oxidation at high temperature, it's possible applications are limited. When exposed to high thermical stress, the chromium plated needle has clear advantages (fig. 080).

Ni-PTFE
The abbreviation for a needle with a Nickel-Polytetraflourethylen surface. Very fine particles of PTFE (grain size <0.3 pm) together with nickel are precipitated without using electricity onto the needle in a nickel bath. These PTFE particles have properties which are very attractive when used on a sewing machine needle. The Ni-PTFE surface has:

• a high anti-clogging effect
• a low friction coefficient
• a high resistance to wear

These result in:

• longer life of the needle
• lower needle temperatures
• higher sewing dependability
• less thread breakage

Nm
1. The abbreviation for the metric size of the needle. Nm means number metric and is 100 times the diameter of the blade in millimeter (mm).
E.g. Nm80 80/100 = 0.80 mm
A size 80 needle has a blade diameter of 0.80 mm.
2. A further abbreviation for the thickness of a thread. Nm also means number metric and is a length (metre) for the thread mass of 1 gramm.
E.g. Nm 100
100 metres of thread weigh 1 gramm see Thread Count

Nomex®
Aromatic polyamide fibre made by Dupont Nemours & Co. It can endure high temperatures (decomposition starts at 370 °C without melting.
Nomex® is also used to make threads (espe-cially for the leather industry). Nomex® is a registered trademark of Du Pont.

Nominal Diameter
This is identical with the size of the needle. see Needle Size

Notched Shank
One or two cutouts in a round shank. The angle between the surface of the notch and the threading direction is important.
E.g.
1 notch needle system 561/1 (fig. 081)
2 notches needle system 561/2 (fig. 082)
the notches are designed to provide an exact positioning of the needle to the hook/looper.

Notch Effect
Notches are defined as cuts which lower the quality of a workpiece.
In a macroscopic range they can be grooves, boreholes or threading. In a microscopic range they can be grain boundaries or inclusions.
The notch effect is the effect these notches have on the distribution of tension across the profile of the the loaded part. The tension can get very high near a notch and will finally lead to breakage.

Notching
Operation step:
A defined wedge-shaped notch is produced in the middle and across a piece of wire. This is for the exaxt positioning of the wire in the press of our Integrated Technology.

Overedge Chain Stitch
Interlocking of one or several threads around the edge of the fabric. Depending on the type of seam and it's quality, there are one, two, three or four thread overedge chain stitches. This type of stitch has the class number 500. E.g.:
501 one thread overedge chain stitch (fig. 083)
504 three thread overedge chain stitch
507 simulated safety stitch, two needle threads and two looper threads.
Adjustment of the thread tension creates different appearances of the seam.

Overedging Seam
Seams which stop the raw edges of textiles from fraying.
Overedging seams can be single or multiple seams which are formed with either one or several different stitch types. The seams are predominantely made with stitch types 500 (Overedging chain stitch) and 600 (Covering chain stitch), the latter especially on elastic fabrics.
Fraying of the edges can also be eliminated by using ribbons (binding). Pipings are also a way to finish the raw edges of a fabric.

Overlock Stitch
see Overedge Chain Stitch

Oversize Bulged at Eye
see Bulged at Eye

Oxide Layer Growth
There is an interdependency between the growth of the oxide layers and the temperature on the needle surfaces iron (Fe), nickel (Ni) and chromium (Cr) (fig. 084). The higher the temperature, the thicker the oxide layer gets. The thickness of the oxide layer increases the‘friction between the needle and the fabric during sewing. When high temperatures are reached during sewing, the chromium plated needle performs much better than a nickel plated or galvanically untreated needle.

Packing Strip
Strip of cardboard-coated polyurethan foam used for packing needles. 10 straight or 5 curved needles are pushed in the strip. The most important part of the needle for the sewing process is in the strip and protected from mechanical and corrosive influences.
The packing strip has the following information:
Front:

• Amount of needles
• Special point
• Parallel systems
• Needle size in Nm and Singer number and eventually a special needle size.

Reverse:

• Manufacturer
• Country of origin
• Internal coding

Parallelism of Flattened Shank
Same distance over the total length of the shank between line a and b with an acceptable tolerance of 0.01 mm (fig. 085). Higher tolerances may result in sewing problems (e.g. stitch skipping)

Parallel System
Needle system which is identical with another needle system but has a different designation. The different designations originate from the fact that

• The sewing machine manufacturers often chose different system designations for a system that already exsists.
• Needle systems with different designations which are geometrically very similar and do not affect the sewing performance have been grouped together.

E.g. Needle system 134 is identical with the following systems (parallel systems) from

sizes 50 to 110
797, 1884, 135x5, 135x7, 135x11, 135x25, 135x65, DPx5, DPx7, DPx25, DPx134, PFx134

sizes 120 to 200
134 KK, 797, 797 KK, 1844, B-134, 135x5, 135x7, 135x11, 135x25, 135x65, DPx5, DPx7, DPx25, DPx134, PFx134, PFx134 KK.

Penetration Force
see Resistance to Penetration

PH-TE Needle
Sewing machine needle with phosphated and then teflonized surface. This needle can be used when sewing man-made fibres or blends of natural and man-made.

Advantage:
The Teflon® coating prevents clogging the needle (melted residues of synthetic fibres) (fig. 086).

Disadvantage:
The phosphate-teflon coating is relatively soft. Depending on the sewing conditions, the coating can wear off very quickly. The effect of anti-clogging is then non-exsistent.

Picking
Operation:
Disentanglement of a pile of needles so that the needles are finally arranged shank to shank and the points are all in the same direction.

Pick Stitching
Attaching interlinings with stitches that are barely visible on the outside of the garment.

Pin
This is a blade (1) with a point (2). The blade is thickened at the opposite end of the point into a head (3) (fig. 087). The blade can be made out of metal (e.g. brass, steel) or plastic. The head can be produced as follows:

• squashing the blade
• pressing a spiral piece of wire onto the blade
• fusing small balls of metal, glass or plastic on the end of the blade. The pins made of brass or hardened steel are mostly nickel plated. The length, thickness and type depend on what they are used for.

A pin can easily be loosened. It can be used for pinning, draping, hemming or in some special cases as decoration such as the garment pins which can be found in many different types and made of different types of material.
see Garment Pin, Needle History

Point
The part of the needle between the top of the eye and the end of the needle (fig. 088). There are round and cutting points.

Point Bending
see Bending

Point Flattening
Operation:
Flattening the point on the side of the long groove (fig. 089) This is only done on needles with excentric points. E.g. Blindstitch needle system 29-34. This flattening ensures that only a few threads are picked up by the needle on the visible side of the fabric. The flattening on system 470 KA enables the seam to be sewn very close to the edge of the fabric.

Point Groove
There is a difference between straight and spiral point grooves (fig. 090).

• Straight
  Groove below the eye on the side of the long groove, short groove or clearance above eye. The point groove on the side of the long groove is only there because of manufacturing reasons. The groove on the side of the short groove or clearance above eye is there to protect the needle thread from high friction when the needle leaves the fabric.
• Spiral
  Groove on the point of the needle and on the side of the short groove or clearance above eye which is angled to the left or the right. The needle thread is protected from high friction during the upward motion of the needle. Spiral point groove needles are usually used in the leather industry.

Pointing
Operation :
Grinding the needle point (fig. 091). We can distinguish between grinding the needles in a soft or hard condition.

Point Length
Distance between the top of the eye and the end of the tip (fig. 092)
Symbol: GO Unit: Millimeter (mm)
There are 3 different types of points: short, medium and long.
The short point, for example, is found on needles for button sewing machines (systems 175x1, 175x3). The medium point is the most frequently used type. The long point is predominantly used on needles for chain stitch machines. Here the point length is extremely important, as it takes part in the formation of the stitch (entering the stitch triangle).

Point Position
see Excentric Points, Cutting Points

Polishing
Operation:
Surface treatment of the needles with paste and brushes to obtain a smooth surface (fig. 093).

Pontoon Clearance above Eye
see Clearance above Eye

Post-bed Sewing Machine
Sewing machine with a column mounted on the base plate. The upper part of the column incorporates the feed dog and the hook or looper. This type of machine is used especially in the shoe manufacturing industry (fig. 094).

PPK Layer
Sewing machine needles with a thin, rough layer of phosphate which is used as a basis for a polymer synthetic layer. This is designed to lower the temperature of the needle during sewing. This is due to the following:

• The polymer synthetic layer has a lower friction coefficient than chrome against textiles
• The nearly black surface radiates more heat.

However hardness tests show that the needles with a PPK layer and chromium plated needles undergo the same heating when used under the same sewing conditions. Also the life time of the PPK layer as with the PH-TE needle depends on the resistance of the fabric. Kooltorr® needles have a PPK layer.

Pre-Grinding Cutting Points
Operation:
This is done manually with the needles in a soft condition. This avoids over-heating when the needles are finally ground in a hardened condition.

Pre-polishing
Operation:
Treating the needle surface with brushes and polishing paste.

Pre-Set Breaking Point
A defined Qotch mostly around the cone section of the needle (fig. 095).
This weakens the needle blade and therefore the probability of the needle breaking here, should it be over-stressed, is very large. The part left in the needle bar after the needle breaks is so short that it cannot penetrate the fabric and cause irrepairable damage.

Pressing Dies
Extremely precise tools for the die-pressing proceedure. They incorporate the negative shape of the eye section or the complete needle blade (eye section and long groove). (fig. 096 and 097)

Price Class
The prices for sewing machine needles are divided into classes. Presently there are 30. The price class depends on the production costs and the demand for the particular needle. Every needle manufacturer more or less uses the same price classes.

Product Inspection
The finished sewing machine needles are inspected under the aspects of the statistic quality control (DIN 40 080) (fig. 098).
The testing entails the following:

• Measuring the main dimensions (shank and blade diameters, distance butt to top of eye, length of the point etc.)
• Checking special shapes (cone shaped point, tip etc.)
• Bending properties (elastic limit, breaking angle, breaking force)
• Eye testing (free of fins)
• Measuring the hardness and thickness of the surface layer (nickel, chromium)
• Visual inspection (blemishes etc.)

Production Inspection
The semi-finished sewing machine needles are inspected under the aspects of statistic quality control during production. This comprises:

• Measuring the main dimensions (shank and blade diameters, distance butt to top of eye, length of point etc.)
• Checking special shapes (cone shaped point, tip etc)
• Bending properties (elastic limit, breaking angle, breaking force)
• Eye testing (free of fins)
• Measuring the hardness and thickness of the surface layer (nickel, chromium)
• Visual inspection (Blemishes etc)

PTFE
Abbreviation for
P Poly
T tetra
F fluor
E ethylen.

PTFE also called Teflon® is known for it's non-sticking effect. It is also very resistant to heat (decomposition not until 400 °C). As it now possible to precipitate fine PTFE particles (grain size <0.3 pm) with nickel without using electricity onto needles, this surface coating is becoming more and more interesting.

see Ni-PTFE
Teflon® DuPont's registered Trademark

Punching
Operation:
A punching pin and a punching die are used to make the eye. An eye that has only been punched cannot be used for sewing. The edges have to be rounded (see sinking) and the surface has to be smoothed (see chemical deburring).

Punching Pin
Tool for making the eye of the needle.

PVD Process
Physical Vapour Deposition. A surfacing process where the surface material is transferred by physical methods (e.g. Vapourization) in the vapour state as a layer on the substratum. This process is used when coating sewing machine needles with Titaniumnitrid (TiN).
The process is more expensive than chromium plating a sewing machine needle. Unfortunately the user will not honour the advantages of the Titaniumnitrid coated needle with a much higher price other than a couple of exceptions.

Radius Clearance above Eye
See Clearance above Eye

Receiving Inspection
Inspection of all goods purchased from outside companies, such as raw, auxiliary and working materials. see Wire Inspection.

Reduced Blade
The blade diameter is slightly smaller in the centre portion than the nominal diameter. The reduced blade reduces the friction between the needle and the fabric (fig. 099).

The result is lower needle heating around the section of the reduced blade.

Reduced Shank
The diameter of the shank is smaller than the diameter of the needle blade (fig. 100). This type of needle is used if the seam requires a larger needle size (e.g. Nm 200) but the borehole of the needle bar does not exceed a specific size (e.g. 1.64 mm).

Regular Round Point
Construction:
The regular round point starts to taper to a pointed cone shortly above the eye. The tip is sharp (fig. 101).
Symbol: R
Application:
This type of needle point is the most frequently used. All types of textiles can be sewn with it, until sewing problems make the use of another point shape (e.g. slim round point, ball point, eccentric round point, round point with triangular tip) necessary.

Relief Grinding
Reduced diameter of the blade just above the eye by grinding the sides (fig. 102). Thus the friction between the needle and fabric is reduced.

Remaining
Thickness of Blade The thickness of the needle blade after milling the long groove(s) (fig. 103). Unit: Millimeter (mm)

Resistance to Penetration
Force acting against a needle penetrating the fabric. The needle is thus exposed to buckling stresses. The resistance to penetration depends on the type of fabric, the amount of plies, the finish of the fabric, the needle size and the shape of the point. The resistance to penetration reaches it's peak shortly before the eye immerses into the fabric. The resistance acting on the needle around the clearance above eye is lower and then gets higher as the thickness of the blade increases. In the lower dead centre the resistance is reduced to zero. When the needle leaves the fabric, the process is reverse but the course is similar to that of the penetration (lower reading though) (fig. 104).

Reverse Twist Point
Construction:
The reverse twist point is wedge-shaped. It's cutting edge is ground at an angle of 45° to the threading direction.
Symbol: LR or RTW
Stitch hole:
Looking in the sewing direction, the cut is slanted from top right to bottom left. It is widened by the needle blade.
Seam appearance: The sewing thread is inserted through the material from top left to bottom right (fig. 105).

Retained strength:
The loss of strength ranges directly behind that of the wedge point (lowest loss).
Application:
Seam with a slight slant of each individual stitch. A twist point has to be used on sewing machines threaded from front to back to obtain the same cutting effect as with the reverse twist point.

Rounded Triangular Tip
Construction:
This point starts to taper to a pointed cone just above the eye. The tip is ground on three sides. One cutting edge is on the side of the long groove. The other two cutting edges are left and right of the long groove (fig. 106)
Symbol: R-SD1
Application:
Sewing fine leather, suede, sheepskin, plastic foils, coated fabrics.

Rounding
Operation:
Grinding the chamfer on the butt (fig. 107)

Round Points
Needles with points ground in a cone shape. The tip may be shaped differently depending on the application of the needle. Needles with a round point are predominantly used on textiles. There are centric and eccentric round points.

Round Shank
Shanks that have a cylindrical shape. At the beginning of 1994 approx. 85% of all used needles had a round shank (fig. 108).

Safety Pin
Pin which is used to securely join mostly textile materials but can be loosened very quickly. This technique is also used on brooches and badges. The modern safety pin has a clip (1), a spiral (2), a blade (3), a point (4) and a cap (5) (fig. 109).

Safety Stitch Seam
Seam which simultaniously overlocks the edges of the fabric and sews a seam. Depending on the stitch type, there are:

• four thread overlock stitch (simulated safety stitch)
• 2 needle threads and two looper threads. Stitch types 507 and 512.
• Five thread overlock stitch (5 thread safety stitch)
• 2 needle threads and 3 looper threads. Stitch type 515.

Schiffli Needles
Needles thatkare used in shuttle embroidery machines.
E.g. Systems 110 S, 110 SA, 854, 854 S

Seam
Straight line of stitching joining two or more plies of fabric. There are:

• sewing seams
• seams formed without thread (glueing, welding)

Seam Puckering
Unintentional puckering forming during or after sewing. There is a difference between:
1. Transportation puckering
2. Displacement puckering
3. Relaxation puckering

1. Transportation puckering. The reason for this is different friction conditions during transport of the fabric. When using a machine with a hopper transport puckering occurs under the following conditions (fig. 110)

• high friction between feed dog and fabric (R1)
• low friction between upper and lower fabric (R2)
• high friction between upper fabric and presser foot (R3)
     R1 + R2 + R3 = transportation puckering
     This puckqing can be prevented by different measures (i.e. teflon coated presser foot = R3 decreases, use of sewing machines with top and drop feed).

2. Displacement puckering. Caused by the insertion of the sewing thread in the fabric. Thus the thread displaces the yarns near the stitchhole. The resulting tension to puckering.

The higher fabric count and the thicker the sewing thread, the higher the chance of puckering (fig. 111).
Proposals that have been made to solve this problem are controversial (use of needles with cuttting points) or can only be carried out with additional expenditure (positioning of the seam at an angle of 15° to the warp direction) (fig. 112).

3. Relaxation puckering This is limited to seams stitched with very elastic sewing threads and high thread tension. The thread which has been inserted with high tension will pucker after sewing (this may take several hours). Variations in humidity and temperature can also play a role (fig. 113).

Seam Strength
Resistance of a seam to vertical or diagonal tension. Depending on the type and speed, there is a difference between static or dynamic strength. The seam strength is influenced by the following:

• Construction of the fabric
• Choice of thread (thickness, material)
• Type of seam, type of stitch, stitch density
• Thread tension
• Type of sewing machine needle (size, point style)

Seam Type
Sewing seams can be divided up as follows:

• Type of stitch
  i.e. lock stitch, chain stitch, overlock stitch
• Arrangement of the stitches
  straight (linear seam), zigzag
• Function
  attaching seam, assembly seam, serging seam, decorative seam
• Way the fabric is folded
  felled seam, non-lapped seam, lapped seam
• Number of stitch rows
  single, double, multiple stitch seams
• Position of the seam in the garment
  sleeve, seat, back, crotch, side

Serging
see Overedge Chain Stitch

Sewing
Joining operation performed with needle and thread. Plies of fabric are joined by stitching (assembly seams). Sewing also creates:

• Attaching seams
• Overedging seams
• Decorative seams

Sewing Machine
A machine which performs a sewing operation.
Only a part of the needle (point, eye and a section of the blade) is pushed through the fabric when using a sewing machine. (An exception are machines which use a needle with two points). A loop is formed in the upwards movement of the needle. The loop is formed due to:

• the friction of the thread in the long groove (an upwards movement of the thread is prevented)
• the thread hitting the end of the eye t. during the upwards movement of the needle

A second thread has to be pulled through this loop to form a stitch or a series of loops have to be interlocked with each other. The sewing machine consists of a casting with head, arm, column and bed. The bed can be constructed as a flat bed, post bed, cylinder or base structure.

The casting incorporates the thread take-up mechanism, hook or looper, the needle drive and feeding mechanism.
In most cases the sewing machine is mounted on a table. This table takes the drive and control mechanisms and any additional devices. The castings of several domestic sewing machines also incorporate the drive (motor or handwheel) and the thread spool holder.
Sewing machine Types can be divided into different classes:

• Type of stitch (lock or chain stitch)
• Type of construction (flatbad, postbed, armbed, base structure or block)
• position of the column (left, right or behind the head)
• Type of drive and stitch control (stitches/cm SPI)
• Type of hook or looper
• Feed
• Type of stitch and seam control
• the number of needles and construction of the machine
• the stitch required (straight, zigzag)
• special stitch requirements (blind seam, covering seam)
• number of simutaneously stitched seams (single or multiple seam)
• the degree of automatic control of the sewing process
• application (domestic, industrial, artisan)
• specification data

Sewing Machine Class
Classification of the various sewing machines by numbers, letters or both together with the manufacturer's name. At least one needle system is assigned to one sewing machine class.

Sewing Machine Needle
Tool for sewing in a sewing machine. It's task is to penetrate the sewing material, protect the thread whilst doing this and guide it throughthe material and finally form a loop. This results in several very important constructional characteristics:

• Shank (shank diameter)
• Blade
• Groove
• Distance butt to top of eye

• eye section
• point

These constructional features can vary depending on the application of the needle. These variations add up to about 800 different needle systems.

Shank diameter (A) and the distance butt to top of eye (01) are determined by the sewing machine (fig. 114). These two characteristics form the first aspect for classification and help to understand the numerous types.

Besides the constructional requirements, the needle also has to stand up to the stresses which result directly from the sewing process. They are mechanical and thermical stresses (Mechanical — buckling and bending, thermical — penetration).
see Resistance to Penetration, Needle Heating

Sewing Needle
Tool for joining. The sewing needle is used when stitching by hand. It penetrates the sewing material and is pulled or pushed completely through. The thread which is threaded in the needle eye is also pulled through the material. The needle has a blade (1) with point (2), eye (3), head (4) and groove (5) (fig. 115).

Sewing needles are divided into different lengths (short, half-long and long) and thicknesses (numbers). The choice of needle depends on fabric, thread and sewing technique.

The basic material for sewing needles is a non-alloy steel containing approx. 0.8% carbon. In a modern production unit, the wire is straightened and cut into pieces twice the length of the finished needle. The blanks are pointed on both ends by a point grinding machine. Then two eyes are pressed in the centre of this blank, punched, rounded and fins are removed and the needle blank is cut in two. After the heat treatment (hardening and intermediate tempering) the needles are nickel plated and packed.

Sewing
Seam A line-shaped joint of two or more plies of material by stitching.

Shank
The part of the needle which is inserted in the needle bar. It is normally secured with a screw.
Diameter, length and special shapes depend on the special design features of the various sewing machine types. We can distinguish between:

• Flattened shank, shank flattened at butt, grooved shank, cooling groove, notched shank, threaded shank, reduced shank.

The manufacturer's name and/or logo and needle size are stamped on the shank (fig. 116).

Shank Diameter
Symbol: A
Unit: Millimeter (mm)
Most of the needle systems have a constant shank diameter for all sizes (fig. 117). Some of the needle systems have different shank diameters increasing at intervals. E.g. System 34 has a shank diameter of 1.64 mm for Nm 60 to 110, 1.90 mm for Nm 120 to 140 and 2.02 mm for Nm 150 to 200.
Some needle systems, starting from a certain size, have a shank diameter which equals the diameter of the needle blade.
In the case of a blade's diameter being larger than the shank's diameter, the shank is reduced to the required diameter.

Tolerances:
Shank diameter < 1 mm ±0.020 mm
Shank diameter 1-3 mm -0.025 mm
Shank diameter 3 mm -0.030 mm
There are about 43 different needle shank diameters not including the needles with shank diameters the same as the blade diameter.

Shank Flattened at Butt
A rectangle is milled in the top of the shank (e.g. system 141x1) This flattened section ensures an exact positioning of the needle to the hook/looper (fig. 118).

Shank Grinding
Operation: The complete length of the hardened shank is ground. The needle shank is rotated under a high-speed,grinding belt (fig. 119).

Shank Length
Distance between the butt and the top of the shoulder (fig. 120).
Symbol: E
Unit: Millimeter (mm)

Exceptions are needles where the shank and blade diameters are the same. Here the shank length is the section where the shank diameter tolerances have to be kept to. The length of the shank is of great significance for the needles resistance to bending forces. The longer the shank, the higher the forces needed to bend the needle. For this reason smaller needle sizes often have a slightly longer shank.
see Short Shank

Short Groove
The short groove always faces the hook of the sewing machine. It protects the needle thread from high friction with the fabric (fig. 121).
Some needle systems have an extended short groove to avoid a possible pinching of the needle thread (i.e. with feed wheel, fur sewing machine, system 176x1). The short groove is a disadvantage when fabrics (jersey) closely envelope the needle. This fabric can be drawn into the stitchhole during the downward motion of the needle. When the needle moves back up, the material rebounds. Thus the loop may not be formed as the needle thread is drawn into the short groove and hook/looper t. completely misses the thread. The result is a skip stitch.
see Clearance above eye (pontoon), Stretch Needle

Short Shank
Needles which have a shorter shank and therefore the blade is longer but the other dimensions remain unchanged (fig. 122). The needle system designation has the additonal abbreviation of KK (e.g. 134 KK). These needles are used when sewing thicker material. This avoids the unwanted widening of the stitchhole or stops the presser foot touching the shoulder or shank of the needle.

Shoulder
Cone-shaped transition from the shank to the blade (fig. 123). The length of the shoulder depends on the ratio of the shank's and blade's diameters and the shoulder angle.

Side Grinding
Needles that are flattened on both sides of the longer groove or eye (fig. 124). This is designed to reduce the friction between the needle and fabric.

Single chain Stitch
Made from a single needle thread which is interlocked with itself (fig. 125).

Single Lock Stitch
Made from a single needle thread which is manually pulled through the fabric with a sewing needle (fig. 126).

Sinking
Operation:
A specially developed technique to rounden the sharp edges resulting from the eye punching operation.

Slim Round Point
Contruction:
This point is cone shaped starting about the middle of the eye (fig. 127).
Abbreviation: R-SPI
Application:
Sewing very fine fabrics such as silk, fabric made from acetate fibres

Small Eye
Eye which is smaller than the nominal width (40% of the nominal diameter of the needle) (fig. 128). The smaller eye is of advantage in cases where the thickness of the thread used is relatively small compared to the size of the needle (proper take-up of the loop by the hook/looper). The abbreviation EO is used most of the time as a suffix to the corresponding needle system.

Soft Straightening
Operation:
Elimination of unwanted changes in the shape of the needle in the non-hardened state.

Spiral Groove
Some needle systems have a groove running in a spiral around the blade.

• straight long groove and a second spiral long groove
• both long and second long groove are spiral

The grooves can be curved either to the left or the right (fig. 129). To determine this, the needle is held with its shank facing the observer. If the groove runs to the left towards the eye, it is a left spiral groove and visa versa.
The spiral groove improves thread protection when stitching stiff and hard fabrics.

Square Point
Construction:
The square point is ground in a pyramid shape. One side is at right angles to the threading direction.
Symbol: Q or SQ
Stitch hole:
The square point has little cutting effect. The small cut is widened by the needle blade and thus, depending on the properties of the leather, more or less tears it.
Seam appearance:
The single stitches of the seam are straight but not Pulled into the leather as strongly as with the cross point (fig. 130).
Retained strength:
The loss of strength almost equals that of the strong cutting triangular point. The reason is the relatively strong tearing of the stitch holes.
Application:
Sewing leather with textiles or leather with a coarse surface structure.

Standardization
Systematic standardization to eliminate the technically and economically needless variety of needle systems.
see DIN

Stitch
The stitch is the result of a thread formation. It can be obtained manually or with the help of a sewing machine. It can be formed

• Without fabric
• Inside the fabric
• By stitching through the fabric
• On top of the fabric
• Distance of stitches (stitch length) Distance between two successive penetrations of the needle Unit: Millimeter (mm), inch
• Stitches
Arrangement of stitches which is repeated regularly. They are sub-divided into standard classes (3 digit numbers):
100 single chain stitches
200 running stitches
300 double lock stitches
400 double chain stitches
500 overedging stitches
600 covering chain stitches
These stitches are summarized in preliminary standard DIN 61 400.
• Stitch formation
  obtaining a thread formation with the help of
  • a needle (needle thread)
  • a needle together with a hook or looper (bobbin or looper thread)
  • a needle together with a hook or looper and a device for adding an additional thread (cover thread)
    During this process the thread can be locked with itself or with other threads. The stitch formation can also be made by several needles and threads depending on the stich type.
• Width of stitch
  Length of a stitch across the direction of feed of material
  Unit: Millimeter (mm); Inch
• Course of the thread
  Section of the thread between two stitches of the needle which is visible on the outside of the fabric

• Stitch density
  Amount of stitches per unit of length
  Unit: stitches/mm (stitches per inch = SPI)
• Stitch length
  see distance of stitches
• Stitch interlocking
  the defined interlocking of a thread with itself or another thread or several other threads depending on the stitch type.

Stitch Skipping
The loop of the needle thread is not picked up by the point of the hook or looper during the stitch formation (fig. 131). This is incomplete and remains undone.
To avoid stitch skipping, you should remember the following:

• Does the needle system correspond to the sewing machine class?
• Is the needle inserted in the needle bar as far as it can go?
• Does the needle size correspond to the thickness of the thread? (see comparison chart needle size/thread count)
• Has the loop take-up position been checked?
• Has the needle turned in the needle bar?
• Is the needle positioned too far away from the point of the hook?
• Is the hole in the throat plate too big?
• Does the needle draw the fabric into the stitch hole? (especially when sewing jersey)
• Is the point of the hook damaged?
• Was a quality thread used?
• Can a thread lubricant help?

Straight Stitch
Sewing stitches in a straight line.

Stretch Needle
Specially designed domestic sewing machine needle for sewing knitted fabrics (e.g. jersey). When sewing, the elastic fabric is forced into the stitch hole of the throat plate. During the needle's upward motion, the fabric springs back. The result is a very small loop meaning that the hook could miss the loop.
To avoid this, the eye section of the needle is constructed so that the hook can pick up the needle thread even if the loop is very small. The shank of this needle is also flattened to obtain a very small distance between the needle and the hook. The needle has a ball point (R-SES).
Needle system: 130/705 H-S

Supplementary Shoulder
The upper part of the blade is thicker than the nominal diameter (fig. 132). The supplementary shoulder increases the bending stiffness of the needle.

Surfaces of Needles
The surface of a sewing machine needle is very important for a number of reasons. Needles have to withstand corrosion (A) for a long time. The needle cannot be made useless by clogging (B). The friction between tie fabric and the needle (C) should be as low as possible. Especially the point area must withstand a considerable amount of wear (D). Also when sewing at high speeds, the formation of oxide layers (E) which can increase the friction has to be avoided.

The following table is a comparison of the characteristics of different types of surfaces on sewing machine needles:

• Protection against corrosion	A
  Anti-clogging effect	B
  Friction coeffecient	C
  Resistance to wear	D
  Oxidization consistency	E

The valuation is 1 = very good, 2 = good, 3 = satisfactory, 4 = sufficient, 5 = poor, 6 = inadequate.

* The low valuation is because the shank of the needle is not coated but just inhibited with chemicals.

Surface Treatment
Processes during which the needle is either cleaned, smoothed or treated in a way so that it will be protected from corrosion. It results in a coating which is suitable for sewing. These surface treatments include:
  Washing
  Chemical deburring
  Polishing grinding
  Nickel plating
  Chromium plating
  Inhibition
  phosphate, teflon coating
  Chemical nickel plating with PTFE
  PVD process

Swaging
Operation:
Reduction by cold forming. The base material is wire. The swaged part is usually the needle blade (fig 133).

System
see Needle System

Tapered Blade
Blade gradually decreasing in thickness across it's entire length to the eye (fig. 134). The cone-shaped blade results in a needle with a higher bending strength although the stitchhole is widened even more depending on the thickness of the fabric. Also, due to this cone shape, the fabric and the blade are both exposed to intensive friction over a longer period. The result is higher thermical stress on fabric and thread.

Tear Drop Point
See Ball Points

Tempering
Operation:
Heating the needles to a temperature of approx. 200 °C for a definite period of time. The needles obtain their elastic properties from tempering.

Textured Yarn
Yarns made from differently produced plain filaments (fig. 135). They are bulky and more elastic. Textured yarn is, for example, used for overedging (overedge chain stitch). Their bulk gives a superior covering effect.

Thermical Behaviour of synthetic Fibres

Thermical Stress of the Needle
When penetrating and rising, the sewing machine needle is heated by the friction between the needle and the fabric. Depending on the sewing conditions, the heat can be so high that the hardness of the needle is effected. The mechanical loading capacity of the needle is reduced especially in the area of the needle used during stitching (i.e. clearance above eye). The needle may bend and finally break. see Cooling Groove, Needle Heating, Needle Cooling, PH-TE Needle, Ni-PTFE, Thread Lubrication.

Thickness of Flattened Shank
Thickness of the shank after flattening (fig. 136).
Symbol: U1 or U1/2
Dimension: Millimeter (mm)

Thickness of Thread
see Thread Count

Thimble
Protection for the finger that pushes the needle through the material. Thimbles are mostly made out of steel, brass, aluminium or plastic. On the surface there are small depressions which stop the needle from slipping. The size of the thimble is the diameter of the bottom opening. The idea to protect the finger while sewing is no doubt as old as the needle itself (fig. 137).

Thread
Means for sewing. When choosing a thread for a particular seam, the following has to be taken into consideration:

• thread count, plies, twist, colour, luster, finish
• breaking load, breaking load strength, loop breaking load, elastic properties
• shrinkage and boil shrinkage
• resistance to water, heat, light, rotting, chemicals and abrasion
• costs
  

Considering these points, industry, trade and private users can choose from a large variety of threads. E.g.:

  1. Threads from natural fibers
      1.1 Vegetable fibers
            Cotton(dull and mercerized),
            flax(linen)
      1.2 Animal fibers
            Silk (continuous = reeled silk,
            thrown = silk schappe)
  2. Treads from man-made fibers
      2.1 Polyester Threads
          2.1.1 Filaments (continuous)
          2.1.2 Monofilaments (transparent)
          2.1.3 Multifilaments (semi-transparent)
          2.1.4 Long staple spun (shappe reeled method)
          2.1.5 Short staple spun (3 cylinder reeled method)
          2.1.6 Textured thread (bulked yarn)
          2.1.7 Core yarn (filament with short staple yarn)
      2.2 Polyamide threads
          2.2.1 Polyamide 6.6 threads
            2.2.1.1 Filament threads
            2.2.1.2 Monofilaments (transparent)

            2.2.1.3 Staple spun threads
            2.2.1.4 Textured threads (bulked yarn)
          2.2.2 Aromatic polyamide threads (Nomex®, Kevlare)
            2.2.2.1 Filament threads (continuous)
            2.2.2.2 Staple spun threads
  3. Blended Threads
      3.1 Core spun threads
          3.1.1 Polyester filament spun with cotton
Thread Breakage
The breaking of thread during sewing can be caused by:

• tensile stress (1)
• fraying (2)
• needle heating (3)
• combination of the 3 (fig. 138) (4)
To avoid thread breakage heed the following:
• use a quality needle
• proper unwinding over the thread guides of the thread spool holder
• proper threading
• check the thread guides for damage or rough edges
• thread tension not too high
• check the needle system (does the needle match the sewing machine class?)
• needle has been put into the needle bar correctly
• the short groove or clearance above eye has to face the hook/looper
• check the loop take-up position
• check the bobbin case opener (double lock-stitch machines)

• use quality thread
• check lubrication of the hook/looper
• check needle size/thread count match (see comparison chart)
• use thread lubrication (especially in case of high needle heating)
• threads quality deteriorates with age

Thread Count
The thread count is usually a one to three digit number (label count). Some thread producers put a further digit with a "/" after the label count. This number refers to the amount of threads twisted together. In most cases, the label count is a length of thread (metres) for a certain mass of thread (grammes). The higher the label count, the thinner the thread.

Threaded Shank
The top of the shank is threaded (fig. 139). It ensures the secure positioning of the needle in the needle bar to resist high tensile stresses (embroidering, hook needles).

Threading Aids
Aids that simplify threading sewing machine needles.
We can distinguish between:
1. Changes to the needle Some domestic sewing machine needles have a slot in the side of the eye (fig. 140) (Handicap needle) The eye end of a sewing needle has a slot and a fork-like opening. The slot opens when the thread in pulled in and then springs back to the original position. This is predominantly used on surgical needles (fig. 141) (Blind needles).

2. Aids
Elastic wire slings (fig. 142)
Hooks (fig. 143)
Slotted slider (fig. 144)
3. Additional equipment on the sewing machine
Hooks or sliders
The thread is blown into the eye

Threading Direction
Direction in which the thread is inserted into the needle's eye (fig. 145). It is always done from the side of the long groove. The short groove or clearance above eye always face the hook or looper. In most cases the needle is threaded from left to right. The threading direction and thus the position of the long groove is indicated by an arrow in the symbols for the shank, blade and the shape of the point.

Threading for Eye Polishing
Operation:
The sewing machine needles are threaded and then polished on a needle eye polishing machine.

Thread Lubrication
Mostly solutions containing silicone oil are used to moisten the thread and have two effects:
1. Reduction in needle temperature
2. Reduction in friction between the hook and thread
Note:
1. The thread should be moistened after it has passed the thread tension discs.
2. The solution must be transferred from the carrier (usually felt) onto the thread.
A thread lubricant can reduce the max. needle temperature by approx. 45%.

Thread Numbering
see Thread Count

Thread Protection
Small elevation in the groove just above the top of the eye (fig. 146). The elevation is designed to reduce the acute angle of the needle thread which is formed during the downward movement.

Thread Tension
Force with which the thread is pulled through the fabric after the stitch formation has been completed. This force depends on the fabric, type of thread and sewing speed. It is usually adjusted by tension discs (with or without guides). These discs are also called thread brake.

The thread tension has a direct influence on the deflection of the needle during the sewing process. The angle ( < ) at which the thread enters the needle eye is very significant. The closer the thread is to the needle, the smaller the force on the needle and the smaller the deflection from it's stitching direction (fig. 147). The rule of thumb for the adjustment of the thread tension (lock stitch sewing machine) is:

The full bobbin is put in the bobbin case. The plate spring on the bobbin case is adjusted so that the latter slowly slides down when held by the thread. The bobbin case is placed in the sewing machine. After this the thread tension is adjusted so that the interlocking of the two threads is in the middle of the fabric.

Tip
The cone-shaped end of the round point (fig. 148). The cone has a base width depending on the type of round point and needle size.
Exception: Round point with triangular tip (R-SD1)

Titaniumnitride
An extremely hard gold coloured coating which can be precipitated onto sewing machine needles using the PVD process at approx. 200 °C. This process is much more expensive than chromium plating and the advantages for sewing do not justify a surcharge. As with the majority of special coatings, the titaniumnitride sewing machine needle will only have a very limited usage. see PVD Process

Triangular Point
Construction:
The point is ground on three sides. One of the cutting edges is on the side of the long groove.
Symbol: D or TRI
Stitch hole:
The strongest cut in the leather is in the feed direction. Depending on the kind of leather, the stitch holes can, despite the relatively high cutting effect, be torn to differing extents.
Seam appearance:
The single stitches are slightly slanted to the left (fig. 149).
Retained strength:
Out of the 6 basic cutting points, the triangular point causes the highest loss in strength.
Application:
The triangular point is predominantly used for coarse leather or leather which is difficult to penetrate. To avoid a high loss of strength, use a minimal amount of stitches per cm.

Triple Needle
Needle with a shank and bar which holds 3 needle blades of equal length with a certain spacing (fig. 150).

Twin Needle
Shank with a bar which holds two needle blades with a certain spacing (fig. 151). With twin needles you can simultaneously sew two rows of stitches when the hook is cross positioned.
Needle system: 130/705 ZWI

Twisted Thread
Made by two or more threads by twisting. The turn of the twist (Z = right, S = left) is usually the opposite of the turn of the single basic threads. Sewing threads normally have a Z turn (fig. 152). Twisting increases the ultimate load and evenness of the thread.

Twist Point
Construction:
The twist point is ground in a wedge shape. The cutting edges and the threading direction form an angle of 135°.

Symbol: LL or TW
Stitchhole:
When looking at the leather in the feed directions, the cut runs from top left to bottom right and is widened by the needle blade.

Seam appearance:
The run of the stitches is straight and only slightly pulled in (fig. 153).

Retained strength:
The loss of strength is just behind the wedge point (lowest loss).
Application:
This point is used for seams with a high stitch density and low loss of strength.

Ultimate Breaking Load
The ultimate load which a thread can endure a tensile strength test.
Unit: centi Newton (cN).
The ultimate breaking load of a thread mainly depends on:

• The fiber material (cotton, silk, flax, PE spun fiber, PA spun fiber, PE filament, PA filament)
• The construction of the thread (length and thickness of the fibers, twist, plies).

The ultimate breaking load of the thread and especially the needle thread is reduced during sewing. Even if the sewing machine is adjusted correctly, this loss still increases if:

• The stitch density increases
• Sewing speed increases
• Higher thread tension
• Coarser fabric
  The loss is higher on a double locksitch than on a double chainstitch machine.

Visual Inspection
Visual inspection of each individual needle after manufacturing. This is done before the product inspection (see Product Inspection). During this visual inspection differences can be discovered between several needles laying alongside each other. Those needles differing from the majority (non-uniform lengths or points, surface etc.) are sorted out. During the inspection the needles are turned using the little finger (Klenkes) (fig. 154).
see Klenkes

VPI Paper
Vapour Phase Inhibitor. Abbreviation for a rust protection made from Dicyclohexylammoniumnitrite. Paper soaked in this is placed inside needle packaging. If dampness gets into the packaging, the VPI hydrolizes and creates a mono-moleculare ferric oxide layer which neutralizes the iron (steel) in the needle.

Wedge Point
Construction:
The wedge point is ground to a wedge shape in the threading direction.
Symbol: P or W

Stitch hole:
This point cuts the leather at right angles to the seam direction. Subsequently, the blade widens the stitch hole.

Seam appearance:
The seam is raised and slightly slanted (fig. 155).

Retained strength:
Of all the cutting points, the loss of strength with the wedge point is the lowest.

Application:
Despite the large amount of stitches per cm, this seam has a high strength. For sewing machines with a cross positioned hook or looper, cross points have to be used to obtain the same cutting effect as with a wedge point. The wedge point is by far the most frequently used cutting point.

Width of Base-line
Diameter at the top of the cone-shaped point which forms the base-line for the shape of the tip (fig. 156). This base-line width is a certain percentage of the needle's diameter.

Wing Needle
Needle with rounded die-pressing fin on both sides of the long groove (fig 157). This needle is used for hem-stitching on domestic sewing machines.

Wire Inspection
After receipt, the needle wire has to pass standard tests. The results of technological, chemical and metallorgraphical tests and examinations determine whether the wire can be used for the production of needles (fig. 158).
Some of the criteria are:

• Diameter
• Surface appearance
• Tensile strength
• Elongation
• Lateral contraction
• Cementite formation
• Grain size
• Surface structure

Zigzag
Sewing stitches in a zigzag arrangement (triangular). There is a difference between two and multiple stitch zigzag.