The stitch regulator has gone bad on my Singer 15-91. It's going to cost $400 to have it fixed; and I was thinking I could probably find another 15-91 in very good condition cheaper than that. I really love that machine.
Anyway, I'm looking at them on e-bay. Nearly every one is listed as an "industrial" machine. The page description shows pictures of them sewing through, like six pieces of naugahyde, or multiple pieces of denim, or leather or canvas. I was a little miffed by that, as I never considered my machine an industrial machine and would never have abused it in that way. It's a little workhorse, but IMO that's just plain abuse. I think they were originally marketed to 1950s housewives, NOT tentmakers and upholsterers.
Just a vent.
Sherry