Cd ,
we know these have a cast in motor boss on them. so singer must have made a motor for that. I have seen ones on C/L for sale that did have some kind of motor mounted there, but look much bigger than the standrad SM motor. I did take a 1.3 amp motor and set that up. but all I had was a piece of old leather belt. when I would hit a heavy seam that belt would slip. Thinking a v belt might have worked. This was using a no so great 31 - 20 wore out race, so it's a bit sticky..
I have two treadle type stands for these, each is missing the wheel. I have spare home type stands now, so I'm playing with the idea of mounting the table top higher so the larger machine will clear the legs and see what the smaller 12" flywheel will do for power LLOL.
Then I saw a machine F/S that had a regular pulley on top that must have been 8 + inches. which is to big , to much of a chance of something getting caught in it like your sleeve and ripping off your arm
anyway those pulleys here are around $25, the piece of alum I made this pulley from, if I had to buy it would have been over $20, add the bolts and gas to go get it. For me is over a 100 mile drive. all this playing adds up quick.
The sevro motors I see the cheapies for $99 shipped, the so called better 550 watts shipped at $120
afew years ago I bought a new arrow motor, works great after breaking in the clutch. This came off a Brennia ( sp ? ) 950 The lady put a servo on that, she loves it.. now
I have had all these clutch's apart (5) noted that the older ones have a lot of grease on them from there ball bearings with no seals ? and how those are service greased, I've ask service guys if the friction surface should be oiled, no one says yes or no.
on the leather working sites, they never seem to get into talking about this type of thing ..