Idlershaft heatup;eccentric bushing tension

[Bake1]

I've recently replaced my 501's idlershaft and eccentric bushing and am wondering what other's experience is with the idlershaft's heat-up at speeds of saw-joint and above. Mine heats up to the point of almost too hot to handle after about five minutes of run time. Is this typical? I regularly lube the shaft with 30wt. non detergent oil. Then, How tight should the set screw be on the eccentric bushing? The manual says the polyV should be flexed about 1/8" under "heavy pressure". What is "heavy"? According to Shopsmith Customer Svc, if the screw is tightened too much, the ears of the housing might break, but they also said that one should err on the side of too tight against too loose. My 510 runs great now, just interested in other's experience.

[charlese]

I've recently replaced my 501's idlershaft and eccentric bushing and am wondering what other's experience is with the idlershaft's heat-up at speeds of saw-joint and above. Mine heats up to the point of almost too hot to handle after about five minutes of run time. Is this typical?
Then, How tight should the set screw be on the eccentric bushing? The manual says the polyV should be flexed about 1/8" under "heavy pressure". What is "heavy"? My 510 runs great now, just interested in other's experience.

All I can tell you is about my case. "Heavy pressure" to me is about one finger pushing about 5 lbs. My belt works fine at that setting. I noticed that my belt is looser (if that is a word) on the edges than in the center. The 1/8" I use is in the center. Suppose the belt is getting somewhat stretched, but since it works it's not going to get changed. I replaced my idler shaft some time ago and am still using the original polyV belt.

As for heating - My Idler shaft doesn't heat up so much that it can be called "hot", but the motor shaft gets pretty hot. Just to make sure we are talking about the correct shafts. The top one doesn't get so hot, but the bottom one gets warmed up pretty good. SS customer service tells me that is normal.

[8iowa]

Six years ago I used my MK V mounted planer to surface a fair amount of hard maple. I think the speed was somewhere up around "S", pretty fast - and a heavy load. The top of the housing just above the shaft got too hot to touch. Not long after that my control sheave bearing failed. Whether on not the failure was related to my project I cannot say for certain. None-the-less, this concerned me so much that I got a power stand for the planer.

If you frequently need to use the headstock for heavy loads over a long period of time, as in planing, It would be a good idea to take a hard look at a power stand.

That being said, my headstock was 17 years old at the time of the control sheave bearing failure and this year I finally sent the headstock back to shopsmith as several other bearings were starting to fail.

[chiroindixon]

At a Traveling Academy ( might have been Doug Reid), we were cautioned to always have the spindle hubs on all the drive shaft outputs. (The splined spindle hubs are the point of attachment for anything driven off the head stock.)

The instructor was emphatic that the spindles doubled as a "heat sink" and worked to dissipate the heat buildup. He stressed to always have them mounted or excessive heat will eventually cause trouble.

I've seen a number of SS's that have had the spindle hubs lost, and never replaced....

Doc

[charlese]

You are right on there,Doc. I couldn't think of the name of those caps on the spindle ends. You know, the ones having a rack and receive the coupler. So I looked in the last catalog and found part #303 - but part #303 is not listed with a description. Therefore used other terms to try to describe the spindle caps.
Guess the only way to order one is to call SS and ask for one of those cap things that are used to turn the coupler attached to the assessory. Got to be specific as you can 'cause the bottom one has a solid end, while the top one has a hole all the way through. The bottom one is the better heat sink.

[reible]

If I am thinking of the right parts here...
301 is the spindle hub (503570)
303 is the idler hub (503738)

If I recall they are just under $3 each

Ed

[billmayo]

I found the following things can cause the idler shaft bearing and headstock to get real hot. If you have the setscrew in the eccentric bushing, overtighten it can also cause heat and possiblely a slight noise when rotated. I use the short part of the allen socket with my fingers to tighten. I find the the poly-v belt must be perfectly aligned also. The poly-v belt pulley (set screw should be checked) on the drive sleeve assy can move a slight amount forward and cause misalignment. The idler sheave poly-v pulley needs to align with the upper poly-v pulley. This is controlled by the idler shaft, bearing and eccentric bushing depth into the headstock. Lastly, a too tight a poly-v belt tension can cause the idler and drive assy bearings to get very hot. I set my poly-v belt tension a little loose and use belt dressing to prevent slip. Do not over-tighten the bolt in the ears of the headstock, they do break off. Shopsmith recommends 20 in/pds but I find 30 in/pds holds better. I use the 1" part of the allen socket with my fingers to tighten, no mechanical assistance on the allen socket wrench.

Bill Mayo