Turning a hardened shaft

[Jeremy_BP]

Hi all,

I'm making an arbor that needs to run in some needle bearings, and has a profile turned on one end. I have some hardened shaft of the proper size, and was wondering if there's any reason I couldn't cut it in my lathe with carbide tooling. Will I break something horribly? I've cut a few hard(ish) things before, but nothing like this.
Thanks!

 

[deverett]

Jeremy

Do you any excess of the hardened shaft? If so, make a trial cut and see what happens. If it is successful, you can carry on with the real thing. If it doesn't then Plan B will be called for!

Dave
The Emerald Isle

 

[Jeremy_BP]

Well, I do have plenty of excess shaft, and inserts are cheap, so I guess that's a good idea. I'll throw science at it and see what happens.

 

[Tin Falcon]

how hard and what size machine do you have.
I usesed to machine IIRC 4150 all the time it had a RC of 38-42.
But that was on a 5 HP cnc Lathe. did not work well on my SB 9".
tin

 

[Jeremy_BP]

I've got a pretty tight 10" Atlas. It does seem to be more rigid that some of the SB lathes I've used.
The shaft is RC 60, but I think only case hardened.

 

[MachineTom]

I've cut hard shafts, shallow cuts,good carbide speed 250-300SFM, strings are bright red hot, beautiful finish with a xx3 insert. Atlas may not be heavy enough, but you will know if it is not, real quick. The speed of the Atlas will need to be 2000 rpm to cut a 1/2 shaft, doc .002-4". If you can't get that fast it will not cut, as it needs that energy to soften the metal to cutting hardness. Other wise it just skips and squeals, with no chips to show.

 

[Jeremy_BP]

Yeah, I get the feeling the machine will yell at me if it can't take it.
I'll do a test cut when I get back to my shop, and I'll report back with the results.
Thanks for the advice you guys. It's invaluable.

 

[te_gui]

If its only case hardened, hopefully your finished diameter is down in the core material. Usually the case is only .030-.060 deep so if you can get under it on your inital cut you should be fine. I have machined lots of hydraulic cylinder rod which has an induction hardened layer under the chrome. It machines fine as long as your first pass is pretty aggressive to get under it.

Brian