reeves drive

[Darren Jamieson]

Hey all, got a quick question that I think someone out there should be able to help with. In one of the threads that I was reading there was a comment about making an ajustment to the arm of the reeves drive to get the RPM's down to more like 300 instead of the 5 or 600 that they all are. I have a cheap lathe that I just can't update at the time and would love it if there was a way to bring down the speed so I can turn the stuff that I want to turn. Any thoughts would help.
Thanks

[John Keeton]

Darren, this is probably the link to which you are referring.

http://www.chrisbillman.com/Projects/LatheSpeed.htm

[Doug W Swanson]

Hi Darren,
Follow the link that John posted and it's pretty easy to do. I did it to my Jet 1236 and it works great.

[Darren Jamieson]

Thanks guys, I new there was something easy I just couldn't put my finger on it.

[Roy Turbett]

Many lathes with a reeves drive can be slowed down by adjusting the fixed sheave on the spindle or replacing a worn belt. On the Powermatic 90 the belt should be within 1/8" of the top of the spindle sheaves when the lathe is in the stop position. If this can't be achieved without the fixed sheave touching the moveable sheave its time to replace the belt. You can also adjust the position of the lower reeves drive so the belt sits lower in the pulley when the lathe is in the stopped position. You can calculate the speed of the lathe by multiplying the speed of the motor by the diameter of the lower reeves and dividing by the diameter of the upper reeves drive.

[Bruce Smith]

Darren the easiest way would be to change the drive sheave on the motor to a smaller diameter sheave. Don't forget you will then be required to change the
V belt to a shorter length one. Good Luck

[Darren Jamieson]

since I very rarely use the highest speed I think that changing the lower sheave would be fine. unless I am wrong about that if you change one it will automaticly change the other????

[David C. Roseman]

since I very rarely use the highest speed I think that changing the lower sheave would be fine. unless I am wrong about that if you change one it will automaticly change the other????

Darren, don't know what make lathe you have, but I'm assuming that your Reeve's drive sheave is a spring-loaded variable speed pulley mounted directly on the motor shaft. I don't think an aftermarket retrofit would be cheap. You can check MSC. I'd think it would also have to be matched pretty closely in characteristics to the sheave on the lathe spindle, as they must work reciprocally, in unison. Even then, unless you can find one that adjusts to a smaller effective diameter than your current OEM sheave when fully expanded, you won't gain any speed reduction. That's easy to check. Set your lathe on the lowest speed, holding the speed lever out (or in, depending on the design) and pushing it gently beyond the last detente until the speed no longer slows, just before things start to chirp and chatter. Look to see how close to the motor shaft the belt has moved. My bet is that you'll already be very near the minimum diameter that your motor shaft will allow.

This should also tell you whether you have extra room to play with at the bottom range. If the lathe slows further as you go beyond the last detente, then the mod John links to in his post may well work. It would for sure be the first thing I'd try. Would also retain your lathe's full upper speed range. Once you change to a smaller diameter drive sheave and go to a shorter belt, you've permanently lost the top end.

David

[Roy Turbett]

since I very rarely use the highest speed I think that changing the lower sheave would be fine. unless I am wrong about that if you change one it will automaticly change the other????

The upper and lower reeves drive work in unison and are the same size for that reason. The position of the belt at the slowest speed is directly opposite the position at the fastest speed. I believe your lathe is like the early Powermatic 90's where the lower reeves drive is mounted directly to the motor. The early PM90 had the same problem with a high start speed. The problem was somewhat corrected when a jackshaft was added on later models where the lower reeves drive is driven by a belt to the motor. This allows the speed range to be changed by changing the size of the pulley on the motor. If you have a three phase motor, an excellent solution is to add a VFD to slow the motor. This is what I did on my early model Powermatic 90. I'm not sure how practical this would be for a single phase motor but someone else may know.