Thread: To harden or not?

Against.

Dodgy if you can't touch up the bore.

Being a morse taper, the part is obviously asymmetric, at least along the length the cooling rates will be different... so on that basis I'd say it's very likely to warp. I imagine you would plunge the part vertically into the water quench.

All things considered, I vote against hardening.

Ray

Just an idea, someone can probably and rightfully shoot me down, but can you make a 0MT taper and plug the hole. Thatll stop air from getting in there and give it quite a bit more strength while it is soft. It wont be able to quench as quickly, but if that part is thin and its on the outside, thatll cool first anyway.

Maybe?

I did make a 0MT plug to hold it while machining. It is a far better fit than I thought it would be given the difficulty in boring the part out. I had thought about that and was concerned that if I got everything up to the right temperature it may decide to join together - not a proper fusion weld but enough to make plug removal difficult.
The tailstock is enough of a learning experience that the extra complication from heat treatment can wait I think...

Thanks for the input (photos posted on completion)
Michael

i would have gone the other way 4140 or P20 and a 10 thou nitride would not have moved a bit tool steel on the other hand hmmmm i don't like to use it unless its fully ground after ht.

Bruce

Originally Posted by Aussie Bruce

I would have gone the other way 4140 or P20 and a 10 thou nitride would not have moved a bit.

Worth thinking about for next time, but it's what I had.

Michael

Michael
I would suggest against heat treatment.
Distortion will cause too many problems.
regards
Bruce

Hi Michael,

If you are OK with the idea of perhaps having to make two of them, perhaps make the first and leave it un-hardened, then when you get the machine up and running you could always make another, heat treat it and then use the machine to grind it to the required tolerance?

Simon

Hi Michael G,

I'm not going to say that I am competent to talk about heat induced distortion.

So...

Have you considered getting the hardening done by someone else and using a different process? e.g. Hard Chroming or TiN plated (unsure about is the later involves heating the part to be TiN'ed or not?) Neither would as cheap as doing it at home.

Cheers

The Beryl Bloke

Hey Michael,

Just wondering where you sourced your W 1 steel from mate ? Is there are web page listing it and prices?

Thanks,

Mike

I didn't get it locally. PM sent.