Turning oil filled bushes!

[C JParticipant @cj88518]

[C JParticipant @cj88518]

Oh dear! I seem to go from one problem job to the next.

As I had to take just 1mm off the O.D. of two oil filled bushes, easy?? in practice my S7 would cut one minute and rub the next until I added enough feed for it to bite, so attaining the size was like playing Russian roulette but I did manage it, and ended up stoning the tool in-situ between cuts, but of course, with a bit of paper on the slide to catch the grit.

So god knows what to use on this material short of a diamond?

[JasonBModerator @jasonb]

**GT inserts work for me.

[C JParticipant @cj88518]

That must be the answer as I was using HSS

[Andrew TinsleyParticipant @andrewtinsley63637]

I have always been told that machining oilite bushes was a no no. This is because the porous bush becomes non porous at the machined face. The bush material tends to smear and fill the cavities. Hence lubrication will be non existent where you need it.

I have never tried it myself, so only passing on second hand information which may or may not be correct.

Excuse me if the OP is not referring to oilite type bushes.

Andrew.

Edited By Andrew Tinsley on 19/05/2020 15:13:05

[C JParticipant @cj88518]

In my case the shaft turns on the inside of the bush, I just couldn't buy a bush with the right O.D.

and at one point I also tried wiping the outside of the bush with alcohol between cuts? and they are oilite

 

 

Edited By C J on 19/05/2020 15:21:12

Edited By C J on 19/05/2020 15:22:58

Edited By C J on 19/05/2020 15:23:43

Edited By C J on 19/05/2020 15:24:21

Edited By C J on 19/05/2020 15:24:42

[KWILParticipant @kwil]

As Jason says **GT inserts, they are so sharp and cut cleanly, the "chips" come away and do not smear.

[C JParticipant @cj88518]

Thanks, I will check them out

[Neil WyattModerator @neilwyatt]

Oilite's advice is mainly to use 'sharp tools':

FROM: oilite.com/Best-Machining-Practices

There are a few basic machining practices required to optimize retaining surface micro-porosity and the self lubricating properties of Oilite® bearing materials.

Cutting tools must be sharp. For this reason, PCD-Diamond inserts are very highly recommended since they hold a cutting edge much longer. This preserves the open-pore structure from which oil can flow freely. A dull tool will smear the pores, greatly reducing the self-lubricating qualities of the material.

Turning: Cutting Feed Rate: 0.002-0.006 IPM
Speed: Oilite® Bronze 375-500 SFM
Speed: Super-Oilite® 250-500 SFM

Roller Burnishing is an excellent choice to modify an ID slightly. Ball sizing can also be used on the ID effectively for final sizing.

Honing and grinding are never recommended on Oilite® bearing materials. Using these methods on any surface which will become the bearing surface will introduce grinding media and could easily smear the bronze pores sealing the micro-porosity.

After extensive machining, bearings should be re-impregnated with appropriate / specified oils. Vacuumed impregnation is recommended. If bearings were not lubricated prior to machining and if cutting fluids were used, that medium must be removed prior to any impregnation of the oil selected for the application. Your authorized distributor can provide oils for re-impregnation after machining.

[C JParticipant @cj88518]

Thank you, that must be The definitive answer

[KWILParticipant @kwil]

If you lubricate them in use, ie on a lathe etc, then use the same oil. Cover one side, fill with oil and apply pressure, finger and thumb if appropriate size, oil will be seen to ooze through the material.

[JasonBModerator @jasonb]

Reaming is what's not good for them and those reaming probably don't use a suitably over size reamer anyway and wonder why the bush is tight when pressed into place

[HOWARDTParticipant @howardt]

Always in the dim past sat the bushes in oil bath for a night. Only machine the non bearing surfaces and press fit the bush using a a rod in the bore which is the required finished size.

But failing that follow the manufacturers recommendations, remember though that this is I assume for hobby use not industrial with all the consequences that go with it. So if it works for you then go ahead.

[bernard towersParticipant @bernardtowers37738]

I use oilite blanks and machine them with hss tools that are honed sharp without trouble and ream them successfully. I machine them dry and when finished fill them with lube and pressurise with your fingers on either end and you’re ready to go.

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