As most of you know, I have this lathe:
It's solidly built, and powerful. One bad thing: the low speed is 600. Actually, on mine, for some reason, the low had crept up to 720. So today, I was going to make a present for my son's 18th birthday, which involved loading a large chunk of wood. I wasn't overly enamored of the idea of spinning a huge unbalanced chunk at 720, so I thought I'd peek inside the reeves drive to see what the problem was.
First, for those of you who don't know how a reeves drive works (I didn't, until today), essentially, you've got two pulleys. One is fixed width. But the other changes width based on how you move an external lever. This changes the "gear" ratio... the belt is squeezed out towards the edge of the pulley as you raise the speed.
Anyway, it seems that, on mine, I had accidentally tried to change speeds with the motor off. The gear attached to the external lever had slipped one notch, hence the 720. So I took two screws out, and pulled out the lever. Then I backed the mechanism back down a notch, reinstalled, and was back to 600.
Cool. But not being one to leave well enough alone, I decided to play a little bit. There are three points of configuration: the lever itself, the way it attaches to the housing, and where the gear meets the actual reeves mechanism. Turns out the top reconfigured speed gets pretty close to 4000. Yikes! But that did tell me I could mess with the speed. So I "overclocked" it the other way (or should I say 'underclocked'?
In any case, I now have a bottom speed of 540!! Don't think I can go much lower than that and still have much power. And what a difference it makes! Was able to rough a very large blank without the usual drama... well, at least with far less drama! Huge, huge difference. Frank, you gotta try it. Not sure if it'll hurt the belt or not, but even if it does, it's worth it.
Really, it's not just that I've reduced the biggest problem with my lathe. This is the first time I've ever hacked a woodworking machine. These are heady days!