8520 Loose Spindle Pulley

[Zertsman]

New to me 8520. Just got the knee gears replaced. All there is as it should be. A cover for them would be nice.

Was moving onto the head and noticed the spindle step pulley had some wobble in it. Got it off and noticed that the bottom bearing does not press on at all. I can drop the pulley over it by hand and gravity will pull it down. Looking at the ID I can see the aluminum is displaced or worn in. Maybe burnished?

There is an old thread about possible corrections. One of the options was to buy the next size up in OD and just turn the ID of the pully a bit larger. Since I need new bearings, this avoids a sleeve, pressing and more precise parts that need to fit together. I thought I may also be able to get wider bearings and not need the snap rings that separate them.

Provided I can find bearings to the right dimensions? how does this solution sound?

Also, my idler pulley has a lot of wear in one of the grooves and is probably worn out from too much belt slippage. I've read on other threads they are not available. How much luck have others had in sourcing other pulleys and machining to fit? I've seen these recommendations, but not the discussion of how it worked.

I also thought about trying to get a wider gage belt, but the smaller pulley diameters may not allow a wider belt around such a small OD pulley.

 

[jcp]

I was able to get new pulleys from Clausing....albeit several years ago. As for the bearings, if you change O.D. the I.D. also changes unless you change series in which case the width changes.....which might help your situation.

 

[markba633csi]

For the pulley you could put a thin layer of epoxy on the inside bore and then re-bore it for a snug fit with the stock bearing
For the idler you need to replace although an epoxy fix would buy you some time at least- nothing to lose since it's already worn
-Mark

 

[woodchucker]

I just put a slug in mine... (6061)
1st I turned it and made it smooth and concentric.
I loctited a slug in that was turned to fit plus maybe 1 thou
I drilled a new hole, then bored it.
I press fit a new bearing in.

 

[Zertsman]

I think I'm gonna go with larger OD bearings. Need to measure the pully to make sure there is plenty of meat. I bet it's fine.

Stock bearings are 47mm OD. Next size up is 52 I think.

Stock width is 14mm with a gap between them. I'm also going to look for wider bearings to do away with this gap. Maybe 16mm will work.

 

[Zertsman]

Well, they have the cone pulleys, but they are over 200 each.. I may limp along with some of the suggestions above and eventually try and turn one. I have the tools, just haven't done something with so many features.

The worst one is the Idler pully. The smallest diameter is totally worn out to a U shape with the belt riding all the way in the bottom of the groove. I'm going to try a segmented belt and see if that buys me some time.

Larger OD bearings for the Spindle pulley seem to be out as well. The OD of the next size pully is right at the inside dimension of the dowel pins that drive the spindle. I don't think I can take out that much material without compromising the pulley.

 

[woodchucker]

Well, they have the cone pulleys, but they are over 200 each.. I may limp along with some of the suggestions above and eventually try and turn one. I have the tools, just haven't done something with so many features.

The worst one is the Idler pully. The smallest diameter is totally worn out to a U shape with the belt riding all the way in the bottom of the groove. I'm going to try a segmented belt and see if that buys me some time.

Larger OD bearings for the Spindle pulley seem to be out as well. The OD of the next size pully is right at the inside dimension of the dowel pins that drive the spindle. I don't think I can take out that much material without compromising the pulley.

so easy to just bore it out, stick some 6061 in there, and recut the bore.
you are over thinking this.

 

[jcp]

I'm pretty sure I still my intermediate pulley. After lunch I go take a look-see....

 

[jcp]

I do have my old idler pulley. The bearing seats measure out at 1.3781 on the lower and 1.2598 on the upper. Enclosed some pics of the vee grooves. The lower one (motor input) is the worst. Maybe it’s better than yours. You can have it for whatever shipping from 74820 is.

 

[Zertsman]

Yes, maybe I am over thinking it. I have one pulley that has problems and don't want to make it worse. Failure is always an option and those hard lessons are not easily forgotten.

I appreciate the offer on the pulley, yours looks way better than mine for sure. The bottom of mine on the motor input is almost .300 wide at the bottom and a full smooth U shape. It was slipping alot for a long time.

I hope to make some really nice ones in the future myself, but with other projects being put off by this, I need to get it somewhat buttoned up and get some work done on the house.

All the advice here is great. Thanks to everyone.

I'm waiting on bearings to get my Head and Spindle back together and then I'll know more for sure.