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#1
Carl

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It seems that some people that frequent this forum have experience case hardening (or something similar anyway) parts.  I am wondering how you are doing this?  I have a machined Miata tranny input shaft that will be used in an RX7 and would like to case harden the machined end.  

 

I have read about a process using Cherry Red Case Hardening material.  Any experience along those lines?

 

Thanks,

 

Carl



#2
Bench Racer

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Carl, got the dimensions from Dave back when I was going to do the conversion. Didn't do the conversion, built a Spec  Miata.  I https://www.mazdatri...ainputshaft.htm    They obviously do not harden the shaft after re-machining. To be doubly sure give Dave Lemon at MazdaTrix a call. 


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#3
Carl

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Dave,

 

I actually had one made a few years ago and the transmission shop wouldn't put it in without hardening it.  At the same time one of my buddies "machined" his with an angle grinder while the input shaft was still in the transmission.  One of the worst "machining jobs I have ever seen.  After about 60 hours of endurance racing the 2nd gear teeth stripped off, but the input shaft and amazingly the pilot bearing seemed to be OK.

 

Probably doesn't need hardening, but kind of interested in trying it anyway.  I will check w/ Mazdatrix though.  I am retired like you so plenty of time (maybe too much) to screw around with stuff.

 

Carl


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#4
Danica Davison

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Call 911 if you're hard for more than four hours.


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#5
Carl

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That was pretty helpful John.


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#6
Carl

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I have to correct my post above.  I talked to the transmission shop that 5 years ago was adamant about having to harden the input shaft after machining it to fit in an RX7.  Turns out they have no idea where to get an input shaft hardened  (Ok John I know I am flirting with additional prurient responses, but I guess I will have to take that chance :) ).  Same owner and pretty sure the same guy I talked to originally.  So I will assume that no hardening was done or will be required.  I will probably test hardening one anyway just to see how much harder it gets.

 

Then I guess I will change my question to:  is it possible to effectively harden the shifter forks using something like Cherry Red Case Hardening?  It is my understanding that the case hardening only affects the top 0.020" of thickness.  Is that enough to help?  I guess the question could also be rephrased as: is that how the shifter forks are being hardened for SM use (I assume they are legal, since they are openly advertised as being used in SM transmissions)?  I would like to harden the shifter forks in my endurance RX7.  

 

Carl



#7
FTodaro

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Better call Saul for hardened shift forks.


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#8
Danica Davison

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It is my understanding that the case hardening only affects the top 0.020" of thickness.  Is that enough to help?  
 

 

Just The Tip.

 

That's all you need, my friend.


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John Davison
Autotechnik Racing / 5x Racing
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#itcouldbeyou

Series Champ - Won a points based series in a Spec Miata Chatterbox - Blah blah blah... Blah blah blah Instigator - Made a topic or post that inspired other We have a Winnah! - Won their 1st race... Congratulations! Bona fide - A bonafide Spec Miata driver

#9
luvin_the_rings

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Carl where are you located? 

 

I would suggest looking for heat treatment shops in your area, however hardening just one shaft can be costly... better to do 2 or 3 at a time......

 

 

https://cwst.com/las...ening/overview/






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