12" Atlas Reverse Tumbler Gear Stud

I bought the gear on ebay - the PN, "10-242", is cast into it. Interestingly, the bushing on the original part is loose as well - very loose. Like maybe 0.020 under.
 
The correct part, then must just be well worn. Should still function but may be a bit noisy and have some extra backlash.
 
So both gears fit the new bushing loosely? Where did you buy the new bushing from?

What about the old bushing? Is it also a push fit in both gears?
 
Yes, very loosely. The bushing came with the new gear off ebay - I'm assuming that's the original bushing that came with the gear. There is evidence of the new bushing having been media blasted on its OD.

The old bushing is loose as well. Both bushings measure about 1.750 to 1.751 OD, while the new gear measures 1.756 in it's bore. The ID of the new bushing is around 1.504, while the old measures about 1.502.

The old gear measures about 1.797 it it's bore.
 
I don't know how well it will work on sintered bronze but I would try knurling and then install it with Locktite. You will need an expanding arbor. There used to be a cheap Chinese set on eBay pretty regularly. I think it went up to 1-1/2".
 
Might be easier to drill and tap down in the root of one of the gear teeth for a small setscrew to retain the bushing. If needed, I could wrap some 0.001" brass shim stock around the OD of the bushing to equalize the gap.
 
paul s said:
If needed, I could wrap some 0.001" brass shim stock around the OD of the bushing to equalize the gap.
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That would be the option I would choose, whatever thickness you can get a good fit with a full wrap to keep it centered. Loctite doesn't grip oilite very well unless you remove all the oil impregnated in it, but knurling like wa5cab suggested would probably be enough to let the loctite hold it

If you had a working lathe you could just make a new bushing :bang head:
 
paul s said:
Might be easier to drill and tap down in the root of one of the gear teeth for a small setscrew to retain the bushing.
Click to expand...

I wouldn't try that. Considering the bushing as being rigid, the set screw will push the bushing off-center. And worse, compared to the gear and the spindle, the bushing is flexible. so after pushing it slightly off center, further tightening will distort the bushing where it is under the set screw. At the very least, knurling does not have either of those disadvantages.
 
paul s said:
... There is evidence of the new bushing having been media blasted on its OD. ...
Click to expand...

Sintered bronze bushings often have a surface appearance similar to one that has had light media blasting, except not shiny.
 
RobertB said:
If you had a working lathe you could just make a new bushing :bang head:
Click to expand...
You mean like this? But then I would have to order a chunk of bearing bronze ($$$). McMaster-Carr has bronze bushings, but the OD is 1.750 -0.000, +0.001, not much help.
wa5cab said:
I wouldn't try that. Considering the bushing as being rigid, the set screw will push the bushing off-center. And worse, compared to the gear and the spindle, the bushing is flexible. so after pushing it slightly off center, further tightening will distort the bushing where it is under the set screw. At the very least, knurling does not have either of those disadvantages.
Click to expand...
Brass shim stock wrapped around the bushing will keep the bushing centered, and drilling the hole with the bushing installed, I could lightly drill a depression in the bushing so that the setscrew wouldn't have to be tightened down much. A little blue loctite on the setscrew, and done.

Or just shim stock and loctite - is the bushing oilite? If so, I suppose that rules out gluing it in.

P8242715.JPGP8242715.JPG
 
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