OT - color differance in bronze and oilite bearings?

[Your Old Dog]

I've found some bearings for a small table saw I recently picked up. Any way of knowing if they are oilite or not? I understand turning oilite bearings to size will damage the microstructure. The ones I've found look to be cast and not turned as they lack the sheen of a turned product.

[This message has been edited by Your Old Dog (edited 07-19-2005).]

[lynnl]

I've always thought oilite bearings were made by a sintering process, which permits the inclusion of oil within the pores.
So if they look to be cast, I'd guess them to be oilite.

[G.A. Ewen]

Oilite bearings are made by the sintering process. This gives them the look that you have discribed.

I turned one not long ago and it worked fine. After turning it I soaked it in oil and then wiped it dry. To test if it had indeed soaked oup oil I put it back in the lathe and gave it a spin. Sure enough the oil came out of it.

I have a small box full of odd sizes. If you give me the size that you need I will look to see if I have it.

[Forrest Addy]

Oilite by definition is a cintered product with communicating porosity like a sponge.

Also by definition its impregnated with oil and it's intended to ne a self lubricating bearing material. Wipe it clean and warm it up or tightly wrap it with paper from a brwon bacg. If it oozes oil it's oilite.

If it's an un-impregnates sinertered product it's porous structure will be evident under 10X magnification. No eye loupe or toehr magnification available in your shop? Shame. Its a necessity for mayny things like cutting tool inspection, material verification tec.

What you have is mystery metal now. If you can ID it as Oilite, fine. Its color will show it to be a copper alloy. What's the next etep? I dunno. Mystery metal is exactly that. I'd use it to bush something low speed and non-critical like a hand cranked awning control or a hand cranked winch.

I sure as hell wouldn't use it in any power driven equipment.

[winchman]

This was discussed here or on another forum some time back. Machining oilite can supposedly "smear" the material and block the porosity that provides oil to the surface. However, I've resized several oilite bushings by taking light cuts with a newly sharpened tool. They have performed well in my applications, where the shaft was 7/8" 4130 tubing.

The "chips" were a sticky dust.
Roger

[lynnl]

I sure don't profess to know, but it would seem to me that in machining you'd be opening up about as many new lubricating pores as you'd likely plug up.

[Your Old Dog]

Thanks guys. Based on what i read here I'm going to assume what I've located are in fact oilite.

Forrest, got a Nikon 10x60 stereo binocular scope that I used for engraving. Has about 3 and 1/2 inches of relief over the work. It may well be the classiest tool in my shop! It was a gift from a kind client who had one of my silver inlays fall out of his Scheutzen Rifle.

G.A. Ewen, thanks for the kind offer but I'
ve found them in a local hardware for $3.00 each. Hell, I might just splurge and change both but thanks again.

Lynn, "I sure don't profess to know, but it would seem to me that in machining you'd be opening up about as many new lubricating pores as you'd likely plug up." I'm not so sure Lynn. I suspect that with my luck I wouldn't get a clean cut and likely a smearing type of cutting action. But, they have the right sizes so I won't have to turn them down.

thanks all.
ray....

[This message has been edited by Your Old Dog (edited 07-19-2005).]

[Mcgyver]

<font face="Verdana, Arial" size="2">Lynn, "I sure don't profess to know, but it would seem to me that in machining you'd be opening up about as many new lubricating pores as you'd likely plug up." I'm not so sure Lynn. I suspect that with my luck I wouldn't get a clean cut and likely a smearing type of cutting action. But, they have the right sizes so I won't have to turn them down.
07-19-2005).][/B]</font>

oilite is a brand, correct? there may be other names that do the same thing. conventional wisdom has it that to avoid the "smearing" a razor sharp boring bar is used - of course the od doesn't matter. If you are machining the od your'e aware that they are slightly oversized to accomodate pressed fit, right?

with that fancy microscope, why don't you be the one to for once and for all scientifically prove or dispell the sintered bronze smearing question?

[PolskiFran]

I believe "oilite" is the generic term for these bearings. I think Boston Bearing Co. uses BostBronze as their trade name. If possible get bearings with the correct id and do the machining on the od if you are concerned about closing the porosity in the bearing.

Frank

[Your Old Dog]

Mcgyver, you'd trust the findings of a rookie? Actually, that's not a bad idea. I have the two old ones to work with. Took them out tonight. I don't have a way to photograph the results as I have no adapters from my scope to my camera.

Polski Fan, I suspect I'll get lucky with the size. This is an old craftsman 6 inch iron table saw. I'll be surprised if I can't use off the shelf bearings from the hardware. I made a drift and got the old ones out with no problem. Hopefully I can beat the new bearlings into submission and into place A press for the shop is still in the wind but not yet here.

I'm still puzzeled by one thing. A couple of folks mentioned turning the outside if resizing was necessary. Wouln't that smear the outside as well? I ask because the mounts for the bearings have holes positioned that look like holes for oiling. That led me to believe that oilite or not, you still have to oil them. The original bearings that came out have no hole or groove in them other than the main bore.

[This message has been edited by Your Old Dog (edited 07-19-2005).]

[wierdscience]

If it is oilite a little heat(bic lighter)and the oil will bubble out.
Also s nick with a file,oilite will cut like butter while say 932 bronze will offer up resistance.

[Mcostello]

By the way guys, don't carry the oilite bushings around in your pocket, or set them on a sheet of paper when outside a plastic bag. Try it ONCE if you must! You will be suprised. Don't ask how I know this one.

[J Tiers]

I think it is OK to bore them.....

It seems to be SOP to press them into a bore, which generally shrinks them a little, and then ream to size. At least repair manuals specify that procedure.

[Evan]

" OILITE and EXCELITE are Registered
Trademarks of Beemer Precision, Inc."

[Evan]

"I don't have a way to photograph the results as I have no adapters from my scope to my camera."

If it has any sort of eye relief just hold the camera to the eyepiece. It's called afocal coupling and it works.