You're right. Maybe thick stock on the band saw, especially for plastics where low speed is needed, but otherwise not that big of a deal on the SPTs strictly as a matter of HP.JPG wrote: ↑Thu Sep 16, 2021 3:55 pm FWIW,one of the slow speed SPTs is the band saw which does not require great hp. Neither do the jig/scroll saw. Belt sander may require A bit more. Disc sanding also does not require great hp. The jointer and planer need high rpms. The planer needs great hp in addition.
So As I see it lower power at slow rpm is not a show stopper for SPTs, Turning large stuff is another matter.
At any speed heavily loading the motor will have side effects, these are not synchronous motors, they can slow down considerably under load, and speed up again when the load is removed. The slow down is alleviated slightly by a flywheel, but only for a couple of seconds. At lower speeds you won't get good response to increasing voltage to speed up the motor. You can end up in a cycle where you have to start the operation at higher than necessary speed, and even then it could still become necessary to unload the motor and let it regain speed.
Any qualitative measure of performance is in the eye of the beholder. In this thread I'm juggling comparisons to the PowerPro, expected performance from 1-1/8 HP motors in conventional headstocks, and my own desired performance for certain kinds of functions. All sorts of configurations would be possible that would satisfy many Shopsmith owners. Some would consider such a conversion because of improved performance for specific functions.