Shopsmith Forums

Hi,

I'm in the process of reconditioning a 510 (circa 1990's?). It seems to be running pretty well at this point, but the idler shaft seems to be getting too hot. After cutting some wood on the table saw, I noticed the headstock was pretty warm all over. The next day I went into my shop and ran the motor for about 1 min. The only part of the headstock that felt hot was the idler shaft. I also took the cover off and felt around inside. Everything felt fine. Running it again for several minutes, the shaft was hotter. With a 1 min run the shaft passes the "1 second test". After running several minutes, it didn't pass the 1 second test (hot to the touch). I checked the poly v-belt tension and made sure the screw holding the eccentric wasn't too tight. Looking through the forums, that's all I could find that might cause this. Other than a bad bearing. Anybody have any other suggestions or am I looking at a new idler shaft assembly (looks like you have to buy the whole thing to get new bearings).

Thanks...

I am hardly an expert here, but when things get too hot, it seems that it is almost always a bearing that is responsible.

Not sure if it's that relevant, but this headstock has the newer, split eccentric with the machine screw mounted in it.

Thanks...

Do you have the hubs attached to the upper and lower auxiliary spindles? They act like a heat sink and help dissipate some heat.

If the belt tension OK and you have recently oiled the control sheave, then I would believe you are OK. I did have to replace one of the newer 2 separate bearing idler shafts with a dual row bearing shaft (older design) where one of the bearings did seize. I have not seen the older style idler shaft dual bearings ever seize or lock up. The noise from a badly worn idler shaft bearing will be easy to hear and feel most times. Yes, the idler shaft can run extremely hot but found a slipping Poly-V belt was the cause most of the time. Too tight belt tension on the Poly-V or Gilmer belt will cause the idler shaft to run quite hot.

Hello, from Texas

New Shopsmith owner here, I too acquired a 1999 Mark V, impressed with build quality thus far, and ability to forever maintaince the unit.

I run my Mark V Jointer at speed and after a few minutes of use, Idle Shaft is very hot, to hot to touch. I will update with a thermal reading soon. Should I be worried ? Unit doesn't make any Obscene noises, and No extreme vibrations ~ everything seems okay. But boy does that shaft get hot and the unit itself seem warm to hot.
its also 99" in dallas

Any response from company mods would be appreciated.

midlowoodman wrote:Hello, from Texas

New Shopsmith owner here, I too acquired a 1999 Mark V, impressed with build quality thus far, and ability to forever maintaince the unit.

I run my Mark V Jointer at speed and after a few minutes of use, Idle Shaft is very hot, to hot to touch. I will update with a thermal reading soon. Should I be worried ? Unit doesn't make any Obscene noises, and No extreme vibrations ~ everything seems okay. But boy does that shaft get hot and the unit itself seem warm to hot.
its also 99" in dallas

Any response from company mods would be appreciated.

Typical unless very excessive. 99 degree ambient greatly exacerbates the temp rise.

Belt alignment can make it worse, so check that.

So very hard to answer a question like this. Living where you do makes it even harder. I live in Tucson and my headstock is warm to touch even now in the early morning. It hasn't been run for hours. If I would go out now and rip three or for 8' boards, I would not be able to hold my hand on the headstock for any length of time. It would not be HOT, not warm.

Belts out of alignment and bearings about to fail are the most likely causes of serious problems. Remain watchful. Or, tear it down, install all new belts and bearings and carry on from there.