Powermatic Model 91 speed control issue

Hey all,

Newbie here. I have a Powermatic Model 91 lathe. It's in very good condition, but I have a problem with the speed increasing on its own. With a bowl spinning it just gradually keeps rising in RPM. I just recently got it back together, new bearings, belts etc. Running great just wants to run away :)

I know a bunch of you guys have experience with the 90 models and this is the same machine, just with the riser blocks.

Any advise?

Thanks,

Ken

Not very familiar with that machine. It has a reeves drive and may need a new belt. They are said to be pretty good machines.

Ken, I had a PM 90. The real PM91 that yours appears to be is quite rare. Nice job on the refurbish. I raised mine to mimic the PM 91, but never had that problem. I suggest you post on the OWWM site as there are many who have the PM lathe and can help.

Ken, does the speed control handle move as the lathe accelerates by itself?

Quote:

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Originally Posted by Bob Ballard

Ken, does the speed control handle move as the lathe accelerates by itself?

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Bob,

Yes it moves right along with the speed. very slowly, very strange

Ken

Thanks William I will try that

Ken,It sounds to me like the problem is in the speed control.dial It should have enough tension to keep the sliding side of the v/s pulley from moving on its own.