Classification of Stitches

An understanding of the common stitch formations permits selection of the most appropriate for any particular purpose. There are two basic stitch formations, lock stitch and chain stitch, with a number of variations in each type.

British Standard 3870: Part 1: 1991: classification and Terminology of Stitch types, is the standard reference to the wide range of stitch types now available for use in garment construction. It defines a stitch as: ‘one unit of conformation resulting from one or more strands or loops of thread intralooping, interlooping or passing into or through material’.

Intralooping is the passing of a loop of thread through another loop formed by the same thread, interlooping is the passing of a loop of thread through another loop formed by a different thread, and interlacing, a term also used in relation to certain stitches, is the passing of a thread over or around thread or loop of another thread.

The first step in producing a stitch on a sewing machine is the formation of the needle thread loop. This step is the same regardless of the type of stitching being produced, or the nature of the machine being used. Failure to generate a good loop will cause many different problems such as skipping, breaking thread, loose stitches, threading bunching up, etc.

Proper formation of this loop depends on the tendency of the thread to bulge away from the needle as it is drawn upward after reaching the lowest point of its stroke - due to inertia and friction against the material through which it passes.

Any interference with the formation of the needle thread loop will result in faulty stitch formation. One of the most common conditions is that the material stitched is not held firmly by the presser foot at the point where the needle passes through, allowing the material to flag, or move up with the needle as it rises. Either no loop is formed at all, or the loop is formed too late. This will result in skipped or broken stitches. You should always refer to the needle, fabric and thread chart to make sure the right size needle is being used. A quick visual inspection of the foot and throat plate is also recommended.

Second step is getting the top thread to go round the bobbin. This is done by the hook coming across at the right time and catching the top thread and pulling it around the bobbin case and bobbin.

Stitch Types can be divided into six main categories:

Class 100 - Chain Stitch

Class 200 - Hand Stitch

Class 300 - Lock Stitch

Class 400 - Multi-thread Chain Stitch

Class 500 - Over-edge Chain Stitch

Class 600 - Covering Chains Stitch

Class 100: Chain Stitches

The stitch types in this class are formed from one or more needle threads, and are characterised by intralooping. One or more loops of thread are passed through the material and secured by intralooping with a succeeding loop after it is passed through the material. Since each loop is in this way dependent on the succeeding one, stitches in this class are insecure and if finishing end of thread is not passed through the last loop or separately through the fabric, or if a stitch is broken, it unravels very easily. The stitches are formed using a blind looper.

·         Stitch type 101 - Single thread chain stitch is used normally when easy withdrawal of the thread is required (e.g. basting). Application: Basting, Button Sewing, Bar Tacking, Bag Closing, Button Hole & Decorative Stitching.

·         Stitch type 103 - This stitch formation is commonly known as a single thread blind hemming or felling stitch. It is produced using a curved needle, which passes left to right through a single or double (hem) folded piece of material, entering and leaving, from the same side of the fabric, carrying a needle thread which is intercepted by a blind looper as it exits the fabric on the right hand stroke. This thread is then carried right to left, back to the needle and interlooped prior to needle penetration. While the needle fully penetrates the inside single or double hem, the other fabric is only partially for a portion of its thickness. As the term “blind hemming” implies, the opposing side to the penetrated seam should show no evidence of a stitching line. Application: hemming, belt loops, padding operations and felling.

Class 100 Stitches

·         Stitch type 104 - This stitch formation is widely used for attaching buttons, snap fasteners, trouser cuff tacks, etc. Normally these machines have a fixed cycle of stitches. A selection of 8, 16, or 32 stitches is most common, with 2 or 3 typing stitches at the end of the cycle to prevent unravelling of the stitch formation, the selected number dependant on the type and size of button (2 or 4 hole, flat or shank) and principally dependant on the type and weight of garment. While 16 stitches would be adequate for a shirt or blouse 18/ 20 ligne button, you would need 32 stitches to secure a 50 ligne button to a trench coat. (40 ligne = 25 mm diameter approx).

Class 200: Hand Stitches

The stitch types in this class originated as hand stitches and are characterised by a single thread which is passed through the material as a single line of thread, and the stitch is secured by the single line of thread passing in and out of the material.

Hand stitching is used at the expensive end of garment production because the consumer expects it at that price. In some cases, machines have been developed to stimulate hand stitching, the best example being stitch type 209 which is used around the outer edges of tailored jackets. This is referred to as pick stitching.

Class 300: Lockstitch

The stitch types in this class are formed with two or more groups of threads and have for a general characteristic the interlacing of the two or more groups. Loops of one group are passed through the material and are secured by the thread or threads of a second group. One group is normally referred to as the needle threads and the other group as bobbin threads. The interlacing of thread in stitches of this class makes them very secure and difficult to unravel.

·      Stitch Type 301 – Commonly referred to as straight lockstitch or Single Needle Lockstitch (SNLS); with a single needle thread and a single bobbin thread, is the commonest stitch used in the clothing industry.

      Lockstitch has enough strength for most purposes. It has the same appearance on both sides, an advantage denied to virtually all other stitch types and of significance in the assembly process of garments, especially where top-stitching is required as well as in seams joining of facings, collars, pockets and many similar garment parts. The stitch is secure because the breaking of one stitch in wear will not cause the whole row to unravel and additionally the end of a line of stitching can be secured by reversing or ‘back-tacking’.

·         Stitch Type 304 – Is commonly used for attaching trimmings such as lace and elastic where a broad row of stitching is needed. It is commonly used to provide a secure but stretchy stitch for the edges of stretch bras and other corsetry.

·         Stitch Type 306 - Two Thread Lockstitch blind-stitch using one needle thread and one bobbin thread. This is more secure than the traditional 103 stitch type. It finds application in hemming and seaming lining to shell fabric. 

·         Stitch type 309 – Is a combination of lockstitch on the top side and zigzag stitch on the bottom side, due to the fact that there two needle but just one bobbin supplying thread to form the stitch. Not much in use, as the bobbin needs to be frequently changed owing to the fact that it supplies thread to both the needles.

·         Stitch Type 315 - Two thread three-Step zigzag lockstitch using one needle thread and one bobbin thread. Typical uses: seaming, topstitching, cover-stitching, knits or woven’s where wide coverage or greater stretch is required. Typically used in foundation garments.

     Stitch Type 316 – Commonly known as Double Needle Lockstitch (DNLS). Here the top and bottom view of the seam is same. It has two lines of lockstitch being produced parallel to each other and simultaneously by 2 needles, which are supplied by the under-threads from their respective bobbins.

Class 400: Multi Thread Chain Stitches

The stitch types in this class are formed with two or more groups of threads, and have for a general characteristic the interlooping of the two groups. Loops of one group of threads are passed through the material and are secured by interlacing and interlooping with loops of another group. One group is normally referred to as the needle threads and the other as looper threads.

The stitches of this class have the appearance of a lockstitch on the top but has a double chain effect formed by a looper thread on the underside. The chain generally lies on the under surface of the material, the needle thread being drawn through to balance the stitch.

Stitches in this class are sometimes referred to as ‘double-locked’ stitches because the needle thread is interconnected with two loops of the under thread. Because of the geometry of the stitch, a two-thread Chain stitch is stronger than a similar lockstitch. An advantage of the stitch class is that both threads forming the stitch are run from large packages on top of the machine so there are no problems with bobbin running out. It is frequently used on long seams in garments such as trousers.

• Stitch Type 401 – This stitch type uses one needle thread and one looper thread. It is often used in combination with an over-edge stitch for economy of seam joining and neatening in bulk production. The stitch produces very strong seams with extensibility.
•  Stitch Type 404 – Used for decorative purposes. It is the zigzag version of 401 stitch type.
• Stitch Type 402 – Uses two needle threads and one looper thread and one blind looper. The appearance is similar to 406, however, narrower than 406. It is used where cord effect is required or a permanent crease, e.g. athletes shorts, tennis shoes, cricket gloves etc.
• Stitch Type 406 - This is one of the commonest of the multi-thread chain stitches constructions, used principally in sportswear, leisure wear, and interlock garments where a high degree of strength and extensibility is required. It is commonly referred to as “two needle bottom cover-stitch.” It involves two needle threads which are interlooped with one looper thread. Threads with good loop forming properties are essential for reliable continuous performance. 
  
• Stitch Type 407 – Uses three needle threads and one looper thread. The effect is similar to 406 except that top side has three rows of stitch. Stitch type 406 and 407 are called flat lock stitches. Stitch type 407 is used for elastic attachment on briefs and panties.

Class 500: Overedge Chain stitch

     The stitch types in this class are formed with one or more groups of threads and have as a general characteristic that loops from at least one group of threads pass around the edge of the material. The most frequently used of these stitch types have one or two needle threads and one or two looper threads and they form a narrow band of stitching along the edge of the fabric with threads intersecting at the edge and preventing the fabric from fraying. All have high elasticity, they do not unravel easily, and a trimming knife on the machine ensures a neat edge prior to sewing.

•      Stitch Type 503 – Two thread Overlock (overedge Chain stitch) formed with one needle thread and only one looper thread. It is less versatile and is used mainly for edge neatening, often referred to as ‘serging’, especially for menswear. It is particularly suitable for trousers because the two-thread construction is less likely to show an impression of the edge after pressing.
  
•      Stitch Type 504 – Referred to as three thread Overlock, formed from one needle thread and two looper threads. The needle thread interloops with both the looper threads which interloop with each other at the fabric edge. It is used for neatening edges and in knitted fabrics for joining seams.
  
•      Stitch Type 512 – This stitch type uses two needle and two looper threads making a total of four threads, hence called four thread Overlock stitch. These are used on light and medium weight fabrics such as lingerie and shirts; they also provide good stretch and recovery when used on knit fabrics. The stitch has a wide bite, great stretch and high extensibility.
  
•       Stitch Type 516 – Is the five thread true safety stitch, using two needle and three looper threads. With one operation two rows of stitches are produced, one row of chain stitch and one row of three thread overlock. It has two loopers below the bed and one looper above, which is called a spreader. It is used for side seams for shirts. Stitch has a medium bite and Moderate Stretch for Seaming on Knits or Woven Fabrics. Stitch has medium elongation along the edge of fabric with better coverage on the fabric edge.
  

Class 600: Covering Chain stitch

Stitch types in this class are formed with three groups of threads, and have for a general characteristic that two of the groups cover both surfaces of the material. Loops of the first group of threads (needle thread) are passed through loops of the third group already cast on the surface of the material, and then through the material where they are interlooped with loops of the second group of threads on the underside of the material. The second and third groups are usually referred to as the top cover threads and the bottom cover or looper threads.

Stitches in this class are the most complex of all and may have up to nine threads in total including four needle threads. They are used in making a broad, flat, comfortable joining of elastic, braid or binding to the edges of garments such as briefs with the scope for a decorative top cover stitch as well as the functional bottom cover over the raw edge of the garment fabric.

The typical application lies in hemming knits, decorative stitch on knits and woven’s, for butt seams, and its high elongation makes it ideal for use in foundation garments.