I saw this motor a while back and it looks like a monster compared to the stock Sherline motor - 750W vs the stock 60W. That's theoretically 12.5 times the juice! It gets up to 4200 rpm vs the Sherline's 6000 rpm so you'll sacrifice some speed for more power. Thing is, all that power gets passed to the spindle via a belt and I have to wonder how much power is lost to slippage.
I honestly do not know if this is a smart move. You would think that more power is better but an equivalent 1HP motor on a little Sherline sounds like a lot. The Sherline is mostly aluminum with plastic gibs and it works really well with the 60W motor; I cannot say how it would do with 1HP but I'm betting you'll have a lot of belt slippage and failure. I guess this is the equivalent of dropping in a big block crate motor into a car with a stock trans and rear end - something is gonna' give. I could be wrong but ...
I've been on a Sherline lathe for almost 30 years now and in all that time I never felt the need for more power or torque. More rigidity, yes. More speed, yes. More power, not really; it will already keep up with larger lathes with the right tooling. I've replaced the drive belt once in 30 years and haven't replaced a gib or had excessive backlash or any other major issues other than rarely changing a leadscrew nut.
Quite honestly, the Sherline motor is matched to the lathe incredibly well. Throw 12.5 times the power into an infrastructure that isn't intended to handle it and you may wind up with a 9 second lathe. You might also wind up with a broken one. My vote is to buy a stock lathe and test drive it (learn to machine with it first), then upgrade if you think it is warranted.
