Question: Reeves drive, Delta lathe

[Ken Grunke]

I have a contractor/friend's Delta 14" lathe in my shop temporarily, to complete a spindle turning job. The Reeves drive is loudly clattering, and inspection reveals it's coming from the inner sheave of the motor pulley--the pulley half closest to the motor.
It's fit on the motor shaft is a bit loose, so I'm wondering if this is the way it is supposed to be, or if the bore I.D. has worn some? Any other owners of this lathe have the problem, and a solution?
Not being the owner, I won't be dealing with Delta, but just wanted to help the guy to a suggested solution. Thanks,

Ken Grunke
member & webmaster, Coulee Region Woodturners
My Home Page

 

[Bill Boehme]

Ken,

I have spent a huge amount of time investigating this particular problem and you have accurately described where the problem is originating. There are several reasons that the movable half of the pulley on the motor shaft starts clattering, but they all produce the same result of wear -- not so much on the arbor hole -- but mainly on the keyway. The primary problem that excites the vibration that leads to the wear is none of the pulley components are especially well balanced and even if they were, the soft die-cast zinc that they are made from means that they won't be that way for long. A good Reeves drive system ought to be made from machined cast iron and incorporate some sort of vibration damping system, otherwise, it will be looking for any old excuse to shake itself apart over time.

After trying numerous things to fix the problem (including such things as truing up the pulleys), I have found two things that are moderately helpful although not a permanent "cure".

Before doing anything else, the pulley ought to be replaced or else it will be analogous to closing the barn door after the horses have already gotten out.

The biggest help seems to be in replacing the 4 mm keystock that comes with the lathe because it is slightly undersized. I bought oversized keystock at Grainger (approximately 0.02 mm oversized). It is cheap, but I had to buy a bundle of five 1-foot sticks so I have a lifetime supply.

The other important thing was to use a better lubrication. I found that using a very heavy synthetic bearing grease that sticks and does not sling off the way that the original stuff does reduced wear considerably and it also provided some damping to almost eliminate the vibration -- at least for a while. Something that worked even better was to apply this stiff grease until it completely filled the area where the spring is located. Next, I made a boot by wrapping several turns of thin plastic (like the grocery store produce bags) strips around the spring and then secured each end with a tie-wrap. I put one of the tie-wraps on the boss of the pulley and the other on the bushing at the other end of the spring. I have found that this does a superb job of damping the vibrations and it keeps the grease in place and clean.

Finally, it is important to check the setscrews on the fixed halves of the pulleys because in all likelihood the vibration has caused them to loosen and when that happens, things start going south in a big hurry. As I mentioned before, the zinc pulleys are soft and when you tighten the setscrews, it can cause the pulleys to tilt on the shaft. Especially check the two setscrews on the motor pulley to make sure that you are not deforming it. This can be done by rotating the shaft and looking for wobble as you incrementally tighten the setscrews. The large spindle pulley has only one setscrew and that is bad so I drilled and tapped holes for two more setscrews spaced at 120-degree increments. The same precaution needs to be taken when tightening these setscrews as was done with the setscrews on the motor pulley.

If you need any more info, let me know.

Bill

 

[Ken Grunke]

Wow Bill, thanks for the most informative reply.
Checking the setscrews was the first thing we did, and of course, this particular one was loose. Another setscrew here would have been called for, very definitely. I read in some machinist book somewhere that if they are 90 degrees apart, that is most effective for some reason I can't recall.
The plastic film boot idea sounds great, I'll look into that. I'll recommend for the owner to get the pulley replaced, also, and refer him to this post.
A couple days ago, I had the same problem with a Jet 1236, which I was using to turn the shorter spindles. The pulley half's bore hasn't started to wear yet, it was just loose setscrews fortunately. Basically the same design, but the Jet has two setscrews 180 degrees apart in both pulleys (for each). I can nip that problem in the bud with this lathe.
Thanks again.

P.S. For lubrication, I've been using bar and chain oil, for chainsaws. Anyone know of any reason NOT to use this stuff? It's sticky, and doesn't collect dirt as much as grease does--but needs application more often. After using it on the Jet, that ran very smoothly for quite a few spindles--it really helps the speed control lever also, making it almost effortless to use.

 

[Bill Boehme]

The synthetic silicone grease does not attract dust nor trap it as badly as the hydrocarbon stuff does because it has a more waxy consistency rather than being gummy (I think that means that it sticks to itself better than it does to other things). The trouble with oil, even bar oil, is that it still tends to run a bit. I also like the viscous damping effect that grease provides better than oil does.

If you would like to get a piece of the keystock, let me know -- otherwise it will just take up space in a drawer here.

Bill

 

[Bill Boehme]

I read in some machinist book somewhere that if they are 90 degrees apart, that is most effective for some reason I can't recall.

What you read is correct, but that assumes the parts are machined reasonably precise and fit together well. In theory, three setscrews can be less effective than two. I think that the guidelines about setscrews are sort of out the window on "not-so-well-made" stuff and that you have to do what you can to fix it. In the cases of the large pulley where I use three setscrews, my main goal was to balance the pulley to minimize side-to-side wobble rather than locking it securely to the shaft, although that was a secondary goal.

Be careful on tightening the setscrews -- I cracked one of the pulleys by tightening too much -- this was the result of frustration of having the setscrew loosen several times even though I had used medium strength Loc-Tite. Another trick is to stack two short setscrews -- as long as you remember that there are two setscrews there. Don't ask me what can happen if you do not remember.

Bill

 

[Bill Boehme]

Ken,

Is your friend interested in a piece of oversized keystock to replace the one on the motor shaft? The cost is reasonable -- $0.00 including tax, title and license.

Bill