One question I get is how to calculate the amount of thread one is likely to use on a given style in production. Naturally, one must measure all the affected seam lines -a task I find to be beyond boring!- and indicate the sort of stitch used to form the seam. You’d think that that thread allocation per seam type would be standard in seam specification tables but it doesn’t seem to be. In the past, I’ve used a crude calculation for a 5 thread overlock to be about 1cm:25cm which includes a waste factor for chaining off and the like. I’ve been looking around for some hard rules to apply and other than the American & Efird site (which is great by the way), I haven’t found much out there on this although there’s a nifty calculation tool at Southern Textile Group but it’s only for single needle lockstitch seams. What are you all using to calculate thread usage and allocation?