Topic: Heat Treating a Resplined Input/Output Shaft?

[Sean King]

I had a Toyota tcase output modified to 32 spline and turned into an input by OTT for mating a stock Toyota front reduction box to an Atlas.....I was going to send it out for cryoing on Monday, but just ran a file across the "new" 32 spline section of the shaft and it's not hardened......

I'm thinking of having it treated back to the stock hardness before cryoing it, but don't know what the Rockwell number (assuming it's a C scale) is for the stock one.

Does anyone know a "general" range of RC for trans/tcase inputs/outputs? (I'm trying to track down the specific number now, but doubt I'll find it).

Do I need to do anything else to the shaft?......does it need to be normalized first, then heat treated and if so, does it need to be induction hardened, case hardened or what (and to what depth)?

What about buying a used Toyota mainshaft (what my new input is made from) and having it tested for either Brinell or Rockwell to determine the factory hardness and then use it as the coupon for the subsequent heat treat on the new input?

Thanks in advance for any help.


Sean

[Sean King [OP]]

Okay, so how about this information:

Anyone know what material the stock output (mainshaft) is made of......8620 gear steel or some other alloy? Anyone know if it's case hardened or induction or what?  I'm guessing case........


Any help is appreicated.

Sean

[WHITE_TRASH]

Id love to help you but thats one bit of info I just dont have.  Id be willing to bet that Marlin knows but he doesnt have much time to spend here these days unfortunately. 

[Sean King [OP]]

Well, thanks for at least replying.  I've also been asking around at Pirate and a few other places.  Seems the general concensus is that the Toyota shaft is probably case hardened to a depth of 15 thousands.

Turns out it's not going to be an issue for me.  OTT has told me that IF I can manage to break my new 32 spline 1.38" input (which they really doubt), they'll make and send me a new one for free. 

I also did some more "testing" and the splines themselves do appear to still be hardened.......OTT said they didn't turn the diameter down at the splines at all before splining it, so the case hardening should still be present.  My first "test" that was at the shaft's end (where they cut it off right before the clutch dog) and that part looked to be turned down significantly deeper so perhaps that's why it was so soft.

In any case, hopefully this info. will help someone else in the future.  Hopefully Marlin will see this someday and post up.  I know this question has come up a few times now on Pirate.

Thanks for the response.

Take care,
Sean