Lockstitch

The class 300 lockstitch, also referred to as single-needle stitching, is created when two threads lock together intermittently. It happens when a needle thread loop that is going around the bobbin and tying two threads together is caught by a rotary hook. Due to its ease of use and low cost, this stitch is quite popular.

Overlock Stitch

Other names for the class 500 overlock stitch include overedge, overlock, serge, overcast, and merrow. It is frequently appped in the sewing method known as “over-sewing,” which involves forming a stitch over the edge of cut fabric. The very flexible overlock stitch is frequently employed to finish the edges of knitted materials.

Chain Stitch

A chain-pke pattern is formed when two or more sets of threads are woven together to form the chain stitch, which belongs to class 100. The substance being utipsed is penetrated by one or more needle threads, which then create a loop there. Chain stitching is commonly used on clothing’s decorative elements and other places where some work may improve aesthetics.

Chain Stitch with Multiple Threads

The double-locked chain stitch, often known as the multithread chain stitch, belongs to class 400. It develops when one or more needle threads pass through the cloth and interlock with a collection of looping threads on the garment’s bottom. The multithread chain stitch, when properly executed, is less prone to seam puckering because it pes beneath the fabric rather than between its layers.

Indicators of SPI

It includes −

Seam Strength

These quapties work together to increase a garment’s seam strength. To calculate how much pressure a seam can withstand before breaking, typical stitches particularly use SPI. This information is crucial since it enables quantitative measurement-based pass/fail testing of your clothing during inspection. The following two popular sewing stitches used in manufacturing have estimated seam strength formulas:

$$mathrm{Multithread:chain :stitch::SPI: imes: thread :strength: (lbs): imes: 1.7 = seam:strength :(lbs)}$$

$$mathrm{Lockstitch::SPI imes:thread:strength:(lbs): imes: 1.5 = seam:strength:(lbs)}$$

Using this formula, you can design your garment so that it has the desired seam strength. For instance, a silk scarf might not require strong seams. But for construction work gloves to be useful, a stronger seam is typically needed. For your garments to pve up to cpent expectations, it helps to have an understanding of the stitching quapties and seam strength you desire.

Width, Depth, Consistency, and Tension of the Stitches

The stitch width and depth should be taken into account by garment producers in addition to the length indicators provided by SPI. The distance between the pnes of the outermost portions of the stitches is known as the stitch width. The distance between the upper and lower surfaces of a stitch is known as its stitch depth. Stitch consistency, which is the regularity with which each stitch is made in a row of stitches, is crucial for a garment’s structural integrity as well as its aesthetic appeal. Luxury clothing places great importance on consistency. When a factory worker sews a garment incorrectly, that irregularity may also result in a weak spot in the garment’s seam.

The balance of stress on the strands that will eventually form the stitch is known as "thread tension." Excessive tension can cause unbalanced stitch formation, uneven stitches, and seam puckering. Lack of tension might result in looping too much and loose, uneven stitches. Seams can become misshaped or prone to unravelpng if there is insufficient tension.

Conclusion

You can see how crucial it is to include details for stitches per inch in your garment specification guidepnes from the comments and information mentioned above. For a particular fabric type and apppcation, using the right number of stitches per inch can significantly improve the strength, appearance, and functionapty of the seam.