Seams and stitches

Seams and Stitches

1. Seams and Stitches Chamal Jayasinghe

2. Seams and Stitches

3. Seam A seam is defined as a line over which two or more fabrics/leathers are superimposed over each other . A seam may also contain the row or rows of stitching threads used to superimpose the fabrics/leathers.

4. Stitch A Stitch is defined as loop or loops of one or more threads when bounds with each other by interlacing, interloping or intralooping or any combination during sewing. Each unit of such structure is called Stitch.

5. Different Methods of Stitch Formation Interloping: It is formed by passing the loop of one thread through the loop of another sewing thread. E.g. Stitch type 401 Intralooping: It is formed by passing the loop of one thread through the loop of the same thread. E.g. Stitch type 101 Interlacing: It is formed when one thread passes over another thread. E.g. Stitch type 301

6. Stitch Types Based on this, there are more than 70 types of stitches out of which around 18-20 types are used most frequently and for ease of identification all the types have been grouped to 6 classes based on the number of the needles, direction of sewing, the form or shape of the stitch, purpose of the stitch, etc.

7. 6 Classes of Stitches 1. Class 100: Single Thread Chain stitch 2. Class 200: Hand Stitch 3. Class 300: Lock Stitch 4.Class 400: Multi-thread Chain Stitch 5. Class 500: Over-edge Chain Stitch 6. Class 600: Covering Chain Stitch

8. 1. Class 100: Single Thread Chain stitch The stitches formed here are from one or more needle by the method of intralooping. Thus, one or more loops of the needle thread are passed through the fabric and secured by looping with the next loop of the same thread after they are passed through the fabric. This type of stitch is very insecure as each loop is dependent on the next loop and a single thread breakage can pull apart the entire stitch . These look similar to that of lockstitch on the face side with the loops on the back. The added advantage of these loops is that it makes the stitch elastic and thus can be used where the fabric needs a little stretch such as in back neck tape in t-shirts. Also, with easy removal of stitch, it is used in basting operations in tailor-made garments. This kind of stitch is often not preferred for seaming operations but is widely used in multi-needle machines, as temporary stitch and blind stitch.  Stitch type 101 or single needle chain stitch is the most common of them along with a 103 single thread blind stitch. The front and back of all the other types are given below 

9. Class 100 Stitch Types

10. Class 200 Hand Stitch These types of stitches are hand stitches that are used for decorative purposes. These are formed by a single sewing thread and the stitch is held by a single line of thread passing from one side to the other side of the fabric. This is mostly used for casual fitting with a simple sewing needle and thread as domestic needs but is also found as topstitch in high-priced garment due to its perfect finish. This can also be done on automatic machines called pick stitch sewing machines but are very slow and are rarely in use. The front and back of all the other types are given below.

11. 3. Class 300: Lock Stitch Lock stitch is the most common form of stitch in ready-made garments and is formed when the thread or threads are introduced from one side of the material to interlace with thread or threads introduced from the other side of the material. The top thread is called the needle thread and the bottom thread is called the bobbin thread. The interlacing of the threads makes the stitch secure and difficult to unravel makes it the most appropriate for a wide range of seams. Also, lockstitch has adequate strength for most purposes with a correct combination of thread and fabric .

12. 3. Class 300: Lock Stitch The main disadvantages of lock stitch are Limited bobbin thread length makes it necessary for changing of the bobbin from when it gets finished. Multi-needle stitching with many closed space needles is not possible due to limited space for bobbin. So, at most two needles can be used in a lockstitch machine. The interlacing of thread limits the elasticity of the stitch and is unsuitable for edge neatening. It is not suitable for knitted fabric due to lack in elasticity. Stitch type 301 is the most common type of stitch with uses in joining garment components, topstitching, etc. Also, buttonholing, button attaching, blind stitching falls in this class of stitches. The front and back of all the other types are given below. 

13. 3. Class 300: Lock Stitch

14. 4.Class 400: Multi-thread Chain Stitch It is a multi-thread chain stitch type where loops formed in one set of sewing thread is passed through the fabric and are held by interloping and interlacing with loops formed by another set of threads called the looper threads. It looks like that of a lockstitch on the front side of the fabric but has a double chain effect created by the looper thread on the backside. Compares to lockstitch, a 2-thread chain stitch is much stronger and since no threads are interlocking with each other within the fabric there are lesser chances of having a puckering in the seam. Another advantage of this is that both the needle and looper thread runs from large cones on the top of the machine unlike that of the limited sewing thread inside bobbin. Also, it runs much faster than that of a lockstitch machine at 8000rpm . Stitch type 401 is the most common of them all and is used in sewing jeans and trousers and is also used with overlock as a safety stitch. Stitch type 406,407 are used for joining lace, braid, elastics with the garment. The front and back of all the other types are given below.

15. Class 400 Multi thread

16. 5. Class 500: Over-edge Chain Stitch It is mostly known as overlock stitch and is formed by one or more sets of sewing threads with at least one set of thread going around the raw fabric edge. All the stitch in this class has high elasticity which does not unravel on thread breakage. Also, the machines are equipped with a trimming knife to make the edge neat before sewing. The width of the stitch may vary from 3-5mm. Overlock stitches are classified according to the number of threads used for sewing such as 1,2,3,4 or 5 thread stitches. Each of these stitches is different in appearance and their respective benefits are:

17. 5. Class 500: Over-edge Chain Stitch 1 thread overlock stitches are used for butt-seaming . 2 -3 thread overlock stitches are used as edge neating seam in woven and knitted garments. 4 thread overlock stitch also known as mock safety stitch provide extra strength while retaining flexibility. 5 thread stitch has two needle threads known as safety stitch which forms stronger seam. Also, the speed of the overlock machine is similar to that of chain stitch machines and can go up to 8000rpm. Stitch Class 504(3 thread overlock) is the most common of all and is used for securing the raw edges of the fabric and for heavy fabric such as denim 514 (4-thread mock safety) is used. This is because 3-thread stitches are prone to seam grinning when the seam is pulled at a right angle to the seam. The front and back of all the other types are given below.

18. 6. Class 600: Covering Chain Stitch It is mostly known as Flatlock stitch and is formed by three sets of sewing thread namely, needle, looper, and spreader. Apart from the needle threads, the other two sets cover the top and bottom part of the stitch. It is the most complicated of all types with up to a total of nine threads including four needles and rest looper and spreader thread.  These are mostly used for attaching tape, lace, braid, elastic to the knit fabric, etc. It can also be used as a decorative stitch. Stitch type 602 is mostly used for the above functions and hemming in t-shirts. The front and back of the rest are given below.

19. 6. Class 600: Covering Chain Stitch

20. Stitch Classification Stitch classification may not be of so much importance when it comes to knowledge but a clear understanding of it is very much important when there is a requirement of identification of stitching to be done in the garment especially in the tech pack. The stitch type then acts as a code at letting the reader know what stitch has to be done over that part of the garment. 

21. Seams - Classification Class 1 - Superimposed seam Class 2 - Lapped seam Class 3 - Bound seams Class 4 - Flat seams Class 5 - Decorative / Ornamental stitching Class 6 - Edge finishing / neatening Class 7 - Attaching of separate items Class 8 - Single ply construction Seams are classified according to the type / number of components used. There are eight classes of seams defined as per ISO 4916:1991.

22. Class 01 – Superimposed Seams These generally start with two or more pieces of material superimposed over each other and joined near an edge, with one or more rows of stitches . There are various types of seams within this class .

23. Class 01 – Stitches Used A superimposed seam can be sewn with Stitch Types 301 or 401 to create a simple seam. The same seam type can also be sewn with Stitch class 500 (Over edge stitch) or Combination stitches (e.g., Stitch class 516 )

24. Class 01 - Applications U sed to create neat load bearing seams for lingerie, shirts, etc. One of the widely used stich types

25. Class 02 – Lapped Seams In this class of seam, two or more piles of material are lapped (i.e., with edges overlaid, plain or folded) and joined with one or more rows of stitches. One of the most popular of this class is the Lap felled type, involving only one stitching operation - a strong seam with fabric edges commonly used to protect jeans or similar garments from fraying. The superficially similar This seam class consists of a minimum of two components and can have different varieties consisting of a number of rows of stitching.

26. Class 02 – Stitches Used The lap felled seam is generally sewn with a 401 chain stitch

27. Class 02 - Applications The lapped seam is the most commonly used seam. It is used in jeans manufacture because of its strong construction. This seam is commonly used for rain wear, and edge stitching front facings on jackets and dresses

28. Class 03 – Bound Seams These are formed by folding a binding strip over the edge of the piles of material and joining both edges of the binding to the material with one or more rows of stitching. This produces a neat edge on a seam exposed to view or to wear. There are a variety of bound seams .

29. Class 03 – Stitches Used 401 chainstich or 301 lockstitch

30. Class 3 - Applications Necklines of t-shirts Bags edge finishing

31. Class 4 – Flat Seam(s) In these seams (sometimes called Butt seams), two fabric edges, flat or folded , are brought together and over sewn with stitches. The purpose of these seams is to produce a joint where no extra thickness of fabric can be tolerated at the seam, as in underwear or foundation garments . The looper thread(s) must be soft, yet strong and the cover thread may be decorative as well as strong. This seam is referred to as a flat seam because the edges do not overlap one another, they will be butted together .

32. Class 4 – Stitches Used Zigzag lock stitch, chain stitch or covering stitch (class 600)

33. Class 4 - Applications This type of seam will consist of two components and can be seen on very fine knitted garments where seams are required to be free from bulkiness

34. Class 5 - Decorative / Ornamental stitching The ornamental stitch is a series of stitches along a straight or curved line or following an ornamental design, on a single ply of material. More complex types include various forms of piping, producing a raised line along the fabric surface

35. Class 5 – Stitches Used Chain stitches

36. Class 5 - Applications The stitching results in decorative surface effects on the fabric e.g., pin tucks , application of braids, etc. This seam type consists of a minimum of one component

37. Class 6 – Edge Finishing / Neatening Edge finishing stitch is where the edge of a single ply of material is folded or covered with a stitch. The simplest of these operations is Surging, Type 6.01.01 , in which a cut edge of a single ply is reinforced by over edge stitching to neaten and prevent fraying. The seam class must include seams whereby the edges are neatened by means of stitches and can be used in cases where the raw edge requires finishing. There is only ever one component to this type of seam. This includes other popular methods ofproducing a neat edge like hemming and blind stitch hemming.

38. Class 6 – Stitches

39. Class 7 – Attaching of Separate Items This seam class involves seams that require the addition of another component onto the edge of a piece of fabric e.g ., elastic braid onto the edge of ladies briefs. This type of seam requires two components.

40. Class 8 – Single Ply Construction This seam class consists of one piece of fabric that is turned in on both edges. It is most commonly seen in belt loops or bets for which a folder can be attached to the machine. This type of seam requires only one component.