"Mark Rand" wrote in message
...
Sorry for the on-topic post, but what-the-heck...

I Have a pinion that is made from the equivalent of 4340 steel (BS EN24).
This
will be hardened to about 50-52HRc to reduce wear from the gear that it
runs
with. The pinion runs on a shaft made from drill rod/Silver steel in a
splash
lubricated gearbox. Should I harden the shaft or leave it soft?



For context, it's one of the pinions/shafts in the apron gearbox of the
Hardinge HLV that I'm rebuilding. The original gears were pretty well
buggered.


Neither material fits the description of embedable or conformable that is
preferred for a bearing metal. On the other hand I hope that I can keep
the
oil fairly clean (unlike the previous owners, who used it as a polishing
lathe)


Ideas, Comments, horror stories, anyone?

Harden it. The best and longest-wearing bushing is hardened steel on
hardened steel. It also requires the best finish and the best fit, because
it won't conform to anything.

Some of the worst are soft steel on soft steel. Hardened steel on soft steel
is only slightly better.

Before ball bearings were common, 10,000 rpm internal grinders used
hardened-steel on hardened-steel bushings. They also used no oil, but that's
another story.

--
Ed Huntress