Bushing Thickness?

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walterwoj

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I have a job I'm working on and I thought I'd ask for some advice here. These are the quick connect and ?main swivel? off a pretty good sized excavator. I'm going to bore out the holes for the pins and sleeve them to fit the pins again. My main question is how thick would you make the sleeves? The holes are only out by .030-.040" now. They already asked me to make a sleeve that is .050 wall thickness. That seems awfully thin to me but they gave me the specs for that one. I can make the others any size I want. I would like closer to .200" wall thickness for strength but I realize we want to take out as little as possible. Any thoughts?

Hole Diameter: ~ 2.000
Oversize Crush: .002"
Inside Crush Comp: .002"
PXL_20240221_224600375.jpgPXL_20240221_224608297.jpg
 
I think that if you allow ,002" PRESS, YOU WILL END UP WITH TOO TIGHT A FIT FOR THE PIN; THAT IS MY EXPERIENCE DOING SUCH WORK, THIN BUSHINGS ARE TO BE AVOIDED, THEY WILL NOT STAY TIGHT IN THE BORES.
 
They should supply you the bushing from the manufacturer. Then you align bore the hole to fit the bushing as per manufacturer specs. You will need a fairly long boring bar, and lots of set up time.
Martin
 
You've got to have a pretty substantial sleeve to stay tight against what's about to happen to it once they turn that machine loose. Substantial enough that it starts to skimp on the parent material, which in turn won't stay tight any more... Kind of a positive feedback loop in a negative direction. The real fix is going to bore back to true, and replace the missing metal. i.e. bore welding. You're also going to want the stock bushings so that somebody in the future has some remote hope of being able to service it at a later date.

OTOH, if this is a temporary repair on an end of life machine..... Whatever you can get in there will be better than nothing, for a little while at least.
 
Press .002” oversized OD, then ream the I.D. To desired size (.002” oversized) then drink beer
 
@benmychree : Thank you for the info. I 'FELT' that .250 was a good number but don't have any experience, I was pretty sure .050 was too little. I'll call the customer tomorrow and recommend a change in the bushing size for the thin one. The other bushings I'll make thicker.

You think over-boring the bushing by .002 will pre-compensate for the crush on it?
 
walterwoj said:
@benmychree : Thank you for the info. I 'FELT' that .250 was a good number but don't have any experience, I was pretty sure .050 was too little. I'll call the customer tomorrow and recommend a change in the bushing size for the thin one. The other bushings I'll make thicker.

You think over-boring the bushing by .002 will pre-compensate for the crush on it?
Click to expand...
I'm thinking that more is better, assuming that the pin needs to be inserted freely. The thing with thin sleeves is that they tend to crush under load and then fall out. I used to bush Case backhoe swing towers with hard bushings made for inner races for needle bearings, we split them in half with an abrasive cut off wheel in the lathe, press them in, then we'd have to do some grinding of the ID to be able to insert the pins, I used a abrasive sleeve on a rubber mandrel powered by a die grinder to do the fitting.
 
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