Ask at your local fabric store for button hole thread, or carpet thread, or topstitch thread and then check to see what is on the label. Look for #69
bonded nylon. I have a couple of extra spools if all that fails.
Email off line. Tensil strength is about 10 lbs. Stitch strength for lockstich
machine is about 10 lbs too, but how you stitch it makes the difference
if you are talking sewing webbing together etc. Different stitch patterns give
different strengths.