[Fot] Verifying if a crank surface is nitrided

[mattspit at att.net]

Most hardness tests rely on making a dent in the material or scratching it. 
All my nitrided parts are black, when fresh, but all nitrideing is not the same. I use salt bath nitriding.
If the crank is black try touching it lightly with a file in an area other than the journal. It should feel hard and not cut it.
Then go the the jounal with the file, try to test it on a place where the bearing does not ride, if it cuts it, it need to be re-nitrided, and perhaps gorund again. If it feels hard like the other part of the crank it is probably fine.

-------------- Original message ----------------------
From: "Scypher at USA.com" <scypher at usa.com>
>
> This is the problem.  The previous owner doesn't know the history and  
> nor do I....  I'd like to know if there a test that can be done (ie  
> surface hardness)
> 
> Thanks
> -S
> 
> 
> On Jul 14, 2007, at 2:16 PM, "Chuck Arnold" <triosan at gmail.com> wrote:
> 
> > I had a stock sized one nitrited, then needed to get it to .010  
> > under [burned a rod bearing running with no oil pressure].  Mt  
> > engine builder said no problem -- nitriitng is good for at least . 
> > 020.  So it depends on at what stage of their grinding life they  
> > were at when nitrad
> >
> > On 7/14/07, Scypher @ USA. com <scypher at usa.com> wrote:
> > I have a number of spare spit 1500 cranks that were clearly nitrided
> > at some point in their life, but are at the 020 030 and even 040 under
> > stage of their life.
> >
> > How do I determine there is enough of a nitrided layer left?  I need
> > to decide about prepping a new crank and nitriding, or turning down an
> > already prepped crank to the next size.
> >
> > Can anyone verify if stock 1500 cranks came with any nitriding from
> > the factory?
> >
> > Thanks
> > -Scott
> > _______________________________________________
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> >
> > -- 
> > Chuck Arnold
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