Back in my 20’s as a lowly Forest Service seasonal firefighter in the middle of Wyoming, the smoke jumpers in Missoula (who manufactured their parachutes and packs in the off season) had a “commercial sewing machine” in the list of inter-governmental surplus so I filled out the form and a month later it showed up table, needles, thread and all.  Honestly I don’t know if it was a 31-15 or 31-20, but it sewed 138 weight thread well and by the end of the summer all the guys on the crew learned to s