Did you know that stitches need specs too? While stitch specs aren’t included on a graded spec sheet with garment points of measure, they are included in other parts of a tech pack.
Each stitch type has an ISO or ASTM code assigned to it. These codes are a universal way to refer to that type of stitch that your factory will know. Industrial sewing machines are associated with what stitch codes they can sew. If you’ve ever seen one of my tech packs, these are the codes that I use in my construction callouts.
Stitch length is another spec. The stitch length is noted in SPI which stands for stitches per inch. The product quality, fabric type, and stitch type all influence what SPI is appropriate.
Some stitch types include several rows of stitches. You’ve probably seen this on the hem of tee shirts. The width between those two rows of stitches is another measurement that needs to be spec’d! Is the needle spacing ?” or ¼”?
Instead of controlling the fit like the graded spec points of measure, stitching specs control the quality of the construction.