Shopsmith Forums

Anybody replaced the idler shaft bearings on their power pro? I got the outer bearing off but the inner bearing is a puzzle. I used bearing puller on the outer bearing no problem. Not sure if the inner bearing is replaceable. The parts diagram does show the bearings are not separate from the shaft so I'm wondering if the bearings are replaceable. I'm afraid to apply too much pressure on the aluminum and broke the belt track. So any ideas appreciated thanks.

I delayed responding to this, was hoping that someone that actually knew the answer would step in. Unfortunately, I have more questions than answers. There is another recent thread on Idler shaft bearing failure, the OP replaced the assembly:
https://www.shopsmith.com/ss_forum/main ... 23288.html
And in that thread JPG mentions another recent thread in which the bearings were described in uncomplimentary terms. I don't have a PP, but I'm planning to upgrade a headstock soon. (My kit is on order, and I hope I still think it was an upgrade 10 years from now.) I don't know any details about this assembly, except to be concerned about anything that fails for multiple users. Especially since the old version M5/MV Idler bearings seem to be relatively bomb proof.
One thing that might help if you are not already using one is a 'bearing separator' style puller.
I'm using the pics at the end of the referenced post. Is the large diameter part of the assembly between the bearings part of the shaft or is it a spacer that you can now remove because you got the outside bearing off? (Other words - Can you determine with certainty which direction the inner bearing needs to go?)
Are the bearings 5/8 inch ID or is there more stepped machining of the shaft to accommodate a larger (metric) bearing? Also can your read the bearing type, I'm wondering about that 16000 RPM thing.
If the pulley is press fit it is possible that heating it to expand it at the same time as pulling it will get it off with less pressure from the puller. Don't overheat it and try to maintain your intuitive feel for how much pressure to apply with the puller. It helps to put the shaft in a metal vice or anything else to give it more thermal mass to keep it as cool as practical compared to the pulley. (If this works heating may also be necessary in order to get it back on.)
If anyone else can provide information, even from a failed attempt at repair, that would be helpful.
What does the inside end of the pulley look like? Can you see the shaft, if yes what is the diameter? Any evidence of a key? My thinking behind this is that it might be best to pull the bearing and pulley together, and it would be nice to know if that is possible.
From careful inspection of the pulley, is there any evidence that it is not a press or interference fit?
Perhaps the OP from the other thread, or someone else that has replaced the Idler, could risk destruction of their bad one for the purpose of photographing how this is assembled to improve the knowledge base.

-David

I started the "keeping score" thread and I will expound as much as I can. I feel the bearings are under designed. They are going to be prone for failure. For the first time in my involvement with SS, I can honestly say that the machine doesn't hold up to the high standards of the past (what does these days).

Now the positive. The replacement shaft and bearings is "only" around 80 dollars, so it is not a bank breaker (like the computer or power supply is). My new shaft came in less than a week and was running again (as only a PowerPro can) in short order. So it is a toss up. They say that the bearings can only be replaced at the factory (unless that has changed). Considering the effort and time to replace the bearings I didn't mind the cost (although I don't like the fact that it has failed this soon).

Hope it helps

Rjent, just out of curiosity, how is the aluminum pulley attached to the shaft, it would seem that would need to be removed and re installed to replace the inner bearing.

AHEM!!!!!

Since thee has a paper weight idler shaft. how about dissecting it?

I am guessing that the rear bearing is easily removed. Then the status of the bearing spacer may be determined. Hopefully it is merely a slip on spacer. If so the front bearing could be removed off the back end of the shaft.

And then the shaft MAY BE salvageable/improved by making the spacer shorter(by the width of two bearings) and two additional bearings added thus doubling the bearing balls ability to withstand stress. Maybe room for a fifth bearing?

JPG wrote:AHEM!!!!!

Since thee has a paper weight idler shaft. how about dissecting it?

I am guessing that the rear bearing is easily removed. Then the status of the bearing spacer may be determined. Hopefully it is merely a slip on spacer. If so the front bearing could be removed off the back end of the shaft.

And then the shaft MAY BE salvageable/improved by making the spacer shorter(by the width of two bearings) and two additional bearings added thus doubling the bearing balls ability to withstand stress. Maybe room for a fifth bearing?

That is exactly what I intend to do JPG. I think a double bearing, or a better bearing could be installed.

rpd, the "pulley" is keyed, so I assume that is removable. I haven't determined yet how hard the shaft is, but my intention is to try to turn the shaft down to accept a better/more bearings. I have a few projects I want to finish, but I will get started soon.

JPG, the bearing spacer does not come off. I tried a bearing separator and the only thing I moved the outer part of the bearing. I have not tried any heat to remove the belt pulley off the shaft. I just order another Idler shaft. The engineers at SS went to a lot of trouble designing the PP idler shaft. The idler shaft is not that expensive but it would have been nice to replace the bearings with better quality bearings.

rjent wrote:I started the "keeping score" thread and I will expound as much as I can. I feel the bearings are under designed. They are going to be prone for failure. For the first time in my involvement with SS, I can honestly say that the machine doesn't hold up to the high standards of the past (what does these days).

Now the positive. The replacement shaft and bearings is "only" around 80 dollars, so it is not a bank breaker (like the computer or power supply is). My new shaft came in less than a week and was running again (as only a PowerPro can) in short order. So it is a toss up. They say that the bearings can only be replaced at the factory (unless that has changed). Considering the effort and time to replace the bearings I didn't mind the cost (although I don't like the fact that it has failed this soon).

Hope it helps

I just don't understand. Why? What are they able to do "at the factory" that can not be done in a well equipped machine shop? Maybe not in a garage shop (like mine).

dusty wrote:

rjent wrote:I started the "keeping score" thread and I will expound as much as I can. I feel the bearings are under designed. They are going to be prone for failure. For the first time in my involvement with SS, I can honestly say that the machine doesn't hold up to the high standards of the past (what does these days).

Now the positive. The replacement shaft and bearings is "only" around 80 dollars, so it is not a bank breaker (like the computer or power supply is). My new shaft came in less than a week and was running again (as only a PowerPro can) in short order. So it is a toss up. They say that the bearings can only be replaced at the factory (unless that has changed). Considering the effort and time to replace the bearings I didn't mind the cost (although I don't like the fact that it has failed this soon).

Hope it helps

I just don't understand. Why? What are they able to do "at the factory" that can not be done in a well equipped machine shop? Maybe not in a garage shop (like mine).

SOP 'We' are not qualified to replace bearings.

Tried heating the spacer to see if it could be removed no luck. Trying to heat the spacer ended up heating the shaft too. Then tried heating the aluminum pulley and same thing.