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Reaming Oil Bushings?

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Kroll

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#1
Good morning guys,I am making repairs to my QCGB which consist of pressing in new oil bushings.Some are normal size and some are kinda odd which will require me to turn the OD of the bushing to press them in.So with these bushing press in I will need to ream some of them.I have only one reamer and use it once,so I know nothing about using reamers.With the bushing in place I will be doing the reaming by hand or drill motor?Could someone walk me through on how to use a reamer by hand and what kind of reamers I need to look for?Thanks guys
 
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#3
If your using Oilite type bushings:
So long as your reamer is sharp and no smearing occurs you should be ok. The pores need to remain intact for proper lubrication. Flush out with oil to clear out any small contaminants. I'm assuming you'll be using your lathe or mill for a straight setup for this operation.
I've been working with Oilite bushing recently and have machined them with good results.
If your using non oilite then no smearing concerns.
 
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#4
You might want to use a adjustable reamer like this.

https://www.ebay.com/itm/SHARS-25-3...674127?hash=item51b935fd0f:g:7JcAAOSwSHZWeq0G

I just picked a size. Have no clue the size range you are working in. They sell these in sets like this, too.

https://www.ebay.com/itm/04-150-901...743936?hash=item5b109cee00:g:XPIAAOSw9qJaXYLS

What I like about these, is that you can carefully aligning the reamer with the other holes that share the same shaft. May have to make a slip bushing to use with the adjustable reamer, most of the time you adjust the reamer after it is put in the bore of the bushing. Snug it to the bore, give it a couple of turns by hand, apply a little more adjustment, rotate again. Measure the bore and determine if more is needs to come out.
I prefer doing this over trying to drive a reamer into a bore with no way to control alignment, causing a misalign bore in the bushing.
 
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woodchucker

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#5
why do you need to ream them after pressing them in? If you are cutting the od, you want about 1 thou over for the press fit. Just press them in, they should not deform. You could heat the casting up using a propane torch to make it press in easier, you could also put the bearing in the freezer b4.

Just curious.
 
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#6
I've had bushings shrink a half thousandth and cause havoc trying to get shafts installed in these small gear boxes. So yeah, you sometimes have to do a little light reaming to get things to go together. Got lucky on one a couple months ago, knew I was going to have to ream it after assembly. Shaft was a little snug, tighter than I usually make things. Took a brass drift, poped the shaft in two places at 90 degrees from each other. Wala, the shaft rotated freely! Sometimes, a little persuasion helps, too.
Take in mind, the OP's gear box is off of a Rockwell lathe they are rebuilding. And if you look in the manual to this lathe in the parts list, it plainly says to ream all bushings after installing. Figure that one out.
 

Kroll

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#7
Thanks guys,with the bushing in hand I can slide it over the shaft but after pressing couple in(one on each side of the bore which leaves middle open for little oil,just like the way it was)I can't slide the shaft in place.But that's ok cause I need to turn the OD of the shaft just to clean it up so maybe then it will fit.Still going to order couple of pieces of 1144 as suggested just in case I mess something up now or later.
 

uncle harry

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#8
Thanks guys,with the bushing in hand I can slide it over the shaft but after pressing couple in(one on each side of the bore which leaves middle open for little oil,just like the way it was)I can't slide the shaft in place.But that's ok cause I need to turn the OD of the shaft just to clean it up so maybe then it will fit.Still going to order couple of pieces of 1144 as suggested just in case I mess something up now or later.
It's been over 20 years that I dealt with sintered bronze bushings. The brand that I used was Oilube. At that time their catalog specified the correct tolerances for hole bores that would retain the bearings and shrink the bore when pressing in. They may still be available and may still publish those dimensional tolerances. They specifically advised not reaming to avoid smearing the porous inside surface thus losing oil flow to the shaft.
 
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cg285

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#9
it's quite common to need to ream after installing. been doing that for years with the manufacturer's approval and instructions. i didn't see the bushing dimensions or shape of the body(s) so no recommendation on what reamers. if you can't chuck it then you will need a pilot bushing as stated - assuming there is room for it.
 
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cg285

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#11
btw if the clearance adjustment is very minor, and a standard size, you may be able to drive a ball bearing through it to broach it
 

benmychree

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#12
The whole point is that reaming may smear the metal inside the bushing, defeating its ability to wick oil through the metal's grains, that is why the manufacturers do not recommend reaming of Oilite type bushings. Pushing a ball bearing through a sintered bushing would do just that. Use of a very sharp reamer may work OK in that respect, with luck. Personally, I avoid the use of Oilite , and instead use SAE 660 bronze; why use an oil impregnated bearing metal, when the mechanism is regularly oiled with the oil can. SAE 660 is much stronger and long wearing than sintered bronze; it has been mentioned that certain service manuals recommend reaming of new bushings after being installed; I'd venture to say that likely, they are referring to solid metal bushings rather than sintered.
 

uncle harry

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#13
The whole point is that reaming may smear the metal inside the bushing, defeating its ability to wick oil through the metal's grains, that is why the manufacturers do not recommend reaming of Oilite type bushings. Pushing a ball bearing through a sintered bushing would do just that. Use of a very sharp reamer may work OK in that respect, with luck. Personally, I avoid the use of Oilite , and instead use SAE 660 bronze; why use an oil impregnated bearing metal, when the mechanism is regularly oiled with the oil can. SAE 660 is much stronger and long wearing than sintered bronze; it has been mentioned that certain service manuals recommend reaming of new bushings after being installed; I'd venture to say that likely, they are referring to solid metal bushings rather than sintered.

I agree
 
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