Stitch Classes and Types

A stitch is the configuration of the intralooping, interlooping, or interlacing of sewing thread in a specific repeated unit.

Stitch Items:

• Intra-looping – is the passing of a loop of thread through another loop formed by the same thread. E.g. stitch type 101.

• Interloping – is the passing of a loop of thread through another loop formed by a different thread, E.g. stitch type 401.

• Interlacing – is the passing of a thread over or around another thread or loop of another thread, E.g. stitch type 301.

1. Stitch properties

Properties of stitches that relate to aesthetics and performance are size, tension, and consistency.

a. Stitch size

Stitch size has three dimensions: length width, and depth. Each may affect the aesthetic, durability, and cost of a garment.

• Length: stitch length is specified as the number of stitch per inch (SPI) and can be an indicator of quality. High SPI means short stitch length and low SPI means long stitch length. Stitch length X SPI = 1.
• Width: the horizontal span covered in the formation of one stitch or a single line of stitching. Stitch width must be specified for certain classes of stitches. Zigzag, overedge, and covering chain stitches that have width dimensions. 
• Depth: is the distance between the upper and lower surface of the stitch. 

b. Tension

Tension ensures a uniform supply of thread and determines how well stitches conformed to the standard formation. Tension is controlled by adjusting a screw that holds the pressure disk. Too much tension causes the seam pucker, uneven stitch etc. 

c. Stitch consistency

Stitch consistency is the uniformity with which each stitch is formed in a row of stitches. Each stitch should be exactly like the previous stitch.

2. Stitch class

Stitch classes are based on the type of thread formation created by a sewing machine. The machine in each class may have the capability of producing several different types of stitches depending on the machine structure and how it is set and threaded. Basic classes of stitch are as follows- 

1. 100 – Single thread chain stitch
2. 200 – Hand stitch
3. 300 – Lock stitch
4. 400 – Multi thread chain stitch
5. 500 – Over edge chain stitch
6. 600 – Covering chain stitch

Class 100: Is a chain stitch type, formed with one or more needle threads introduced from one side of the material only. Chain stitch is elastic and thicker than lockstitch and can easily be raveled; particular care is required to prevent runback from the last stitch. Used for temporary stitching or for blind stitching.

Class 200: Is a hand stitch type, formed by a single thread passed from one side of the material to the other in successive needle penetrations.

Class 300: Is a lock stitch type, is formed by a needle thread or threads, introduced from one side of the material, interlacing with an under thread. 

Class 400: This is a multi-thread chain stitch type, which is formed with two or more groups of threads having the general characteristic of interlacing interloping of the loops of the two groups. Non-ravel, strong, good elasticity, less likely to cause seam pucker due to structural jamming.

 

Class 500: Is an overlock/ overedge stitch type, formed with one or more needles and/or looper threads with at least one thread passing around the edge of the material being sewn.

 

Class 600: Is formed with two or more groups of threads, has a general characteristic that two groups of threads cover the surfaces of the material.

3. Types of sewing machine

Industrial sewing machines are classified according to their intended use and the means of forming stitches. Machines in each class may have the capability of producing several different types of stitches depending on the machine structure and how it is set and threaded. Many stitch types are only appropriate for certain sewing operations and product lines.

Sewing machine may be categorized according to

• Purpose
• Stitch type 
• Machine bed