# Re heat treatment on vintage knives



## mdoublestack (Jan 14, 2014)

Is it possible to do a fresh "re heat" treatment on say vintage carbon steel knives, to increase edge retention, raise hrc?


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## jklip13 (Jan 14, 2014)

Theoretically yet, The heat treatment of any steel can always be improved. Practically not really. The knife has already been ground very thin and there could be some serious warping from the heat treatments. The straightening of the blade would be a nightmare and pretty prohibitive to anyone but a master.
Even if it could be done, the particular steel might not necessarily perform much better at higher HRCs because of embrittlement.
After the HT and tempering cycle the edge of a fully thinned kitchen knife would probably look like spaghetti


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## jklip13 (Jan 14, 2014)

It might be possible to turn a chef's knife into a slicer however by bringing the edge back before HT, thus thickening the edge and lessening the warping. The knife would then have to be reground after HT in order to thin it back out


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## knyfeknerd (Jan 14, 2014)

I'm pretty sure. IIRC, Marko talked about a way to do this a while back. I've thought about this before using a conventional oven, but have never tried it and don't know enough any way. I wouldn't have a way to test the HRC afterward.


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## Lefty (Jan 14, 2014)

Marko was talking about tempering an over-hardened knife, I believe.


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## Delbert Ealy (Jan 14, 2014)

Heat treating for me has always been one of the most critical factors in making knives, and I have spent many years at it and I am very good at it. Reheat treating a finished kitchen knife would be very difficult, beyond my ability. It is most likely that the edge will be crinkled, and not be able to be straightened. 
Thanks,
Del


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