# what is the best edge thickness before the heat treatment ?



## Lemieux (Dec 6, 2014)

Hi guys, I want to give a try at making a blade and I'm wondering how thick should I leave to the edge before the heat treatment ? and/or before final sharpening :confusedsign:

Thanks a lot for your answer !!


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## stereo.pete (Dec 6, 2014)

It depends on the blade steel and the quality of the grind. If you are going to have Peter's Heat Treating do it (one of the best out there) they recommend nothing thinner than .015. There are some steels though that you can take to .01 and they will be fine, again it takes some research to know what you need to do.


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## XooMG (Dec 6, 2014)

When I did heat treating, I much preferred a thick edge to reduce the time at temperature for the edge (i.e. edge and body reach critical and stay near it for about the same amount of time). Cracking and warping were secondary considerations.


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## Lemieux (Dec 6, 2014)

Thank you stereo.pete for your fast answer and tips, as I live in Quebec I think I will go for a company in Montreal or in Ontario for heat treatment. I was thinking to use ats-34 because it is cheap, but is 154CM or CPM S35VN even if it is harder to work is more stable during heat treatment ?

is carbon steel like O1 is more stable than stainless steel during heat treatment ?

I keep looking on the net but it is hard to find answers, do you know any good site or key word I should look for ?

One last question guys, do you know a better site than admiral steel for ordering small order of blade steel?

Thank you very much


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## Lemieux (Dec 7, 2014)

Thank you XooMg for you answer, I don't know very much about steel but instinctively I would say that your way is the best way... What is the steel you use and how thick do you leave on the edge ?
I will explain more what I will try to do. I have a friend that own a cnc machine shop, and about 6 years ago I was showing him my chef knives that I pimped and he was talking to me about is idea to make blade out of cnc machine, at that time I knew that it could be a good idea, but not something I can do. In the past week I realized that many knives maker were using cnc and I watched many video on youtube about that, luckily my brother is from scratch an awesome cnc programer , formally a geologist engineer that never work on that and just like working on machine however by paying him with great knives I should be able to get a 3D tool path on the three 2D model he already help me to make (it was not easy to involve him into that but once he started, he just discover the law of knife edge ''in 2D'' every chef knife edge are made out of three composed circles circumference, hard to understand but it is real, the circles are huge compare to the edge size. He told me that he could do a programme for that, obviously he never did it, if one days he build it I will post it on the forum and if someone really want it I can send his email, he is really not about money, so do I, but for some buck he would probably do it, but do not expect to own the right; ) that was a long parenthese, the thing is that my friend is more my bro friend and he is the owner of a quite big machine shop, he is a metallurgist engineer that took the shop of his father, so even I could maybe get some good price from him, I need to bring a tool path, that I will obviously need help from my bro, then work with is programer to get from a 0.100 sheet plate a chef knife blade, ready to heat treatment and then do the final work. Having it machined twice, would involved way too much cnc work and would cost too much, as a poor chef my question is...
How close to finished blade can you get before heat treatment ? 
what edge thickness on what steel ? 

the main question is, for a kitchen knife, of course : During heat treatment, which steel has the less deformation (cracking and warping) ?


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## stereo.pete (Dec 7, 2014)

FYI: I've also heard it recommended by some experienced blade smith's that if you are using stock that is .090 or thinner, you should do all grinding post heat treat for what it is worth.


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## tim37 (Dec 30, 2014)

I have sent knives to Peters and they recommend .010" min. for the edge. I am using M390 and S35VN, both PM stainless. Both have high Vanadium content so the thinner the better before HT. Sanding after HT is a bear.

Tim


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