Classic Cars Forum Vehicle preservation, restoration and discussion!

[ukdave2002]

Do any of you have any experience of case hardening a machined steel component?

The layshaft in the Morris 8 gearbox is quite badly worn, it’s a simple 5/8” bar, drilled with a couple of oil ways. I can turn one up on the lathe, not a problem. However it needs to be case hardened, so I have got myself some case hardening compound. My concern is that as the case hardening process involves heating to cherry red and quenching in water I may distort the accurately machined layshaft?
Or should I expect to “final “machine the case hardened shaft, which doesn’t sound good on 2 fronts ; 1) I can imagine turning case hardened steel will be problematic , 2) it will be removing the case hardening!

Any advice appreciated!

Cheers Dave

[Phil - Nottingham]

Machining after casehardening if that is actually possible without specialist tools or stoning will removing it

Distortion should not be problem if a regular shaft of good quality steel but it must be tested after doing it.

Best to leave to experts?
_________________
Phil

[peterwpg]

Case hardening is the application of case hardening powder or paste to the surface of a red hot piece of steel.

Tempering of steel is done by heating, to a lesser degree and watching the color straws change color. The steel is then quickly quenched when the correct color is seen.

Case hardened steel can only be ground.

Google "Case Hardening" for more info.

We used to play around with this stuff at school, minus of course the full hazmat gear that ones seems to have to wear today just to open a can of paint.

[Ghost]

peterwpg – says ”Case hardened steel can only be ground”.

What about carbide tipped tools? I was given a bucket of HSS lathe tools years ago when a local workshop closed down. As I don't do adventurous stuff on my lathe I've never bought any modern tools for it. But I'd be tempted to go carbide if it could cut really hard stuff.

[PAUL BEAUMONT]

To harden steel you have to increase its carbon content. Case hardening is a cheap way to do this and maintain a maleable core, but it does involve nasty chemicals - often cyanide - as the source of the extra carbon. I am wondering why the shaft is cased in the first place - does it have needle roller bearings running directly on it? or is it just for cheapness?
It is usual to finish grind such shafts.
I am wondering if machining a shaft from a better grade of steel would suffice presuming that the vehicle will not see immense work and that the original cased shaft has clearly failed?