Some of those old Singers are beasts - I picked up a $10 old electric one, I think I found it was late 50’s/early 60’s if memory serves (rarely does) to reupholster a seat on my boat. No way my wife’s modern one would punch through all those layers. That thing did it without even slowing down enough so I ended up adding more reinforcement to the seams. Still looks like shit because I don’t really know how to sew, but I was impressed with the punch those old machines put out.