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Old 08-17-2018, 12:26 PM
samuraistuart samuraistuart is offline
Steel Addict
 
Join Date: Dec 2012
Location: San Antonio Texas
Posts: 163
That most certainly is NOT a stupid question. It is extremely valid and a question that every maker needs an answer to. This is also a question where you will get differing opinions. I'll try to steer you the best I can.

The thickness of the edge PRIOR to heat treating really depends on the steel itself. If we are talking carbon steels like 1084, 1095, O1 and such, the THINNEST edge for an oil quench is 0.020" thick. That is really the thinnest you can get an edge before it will "bacon" warp. Like an "s" curve! Ask me how I know! But I do NOT recommend going that thin prior to HT. To prevent edge warps, take it down to 0.030" for a safer minimum. 0.040" is even better and safer. A dime is about 0.050" thick, a good reference and a good edge thickness, too. You will have a little more to grind off after heat treating, but that's just part of the process.

Stainless steel is a different animal. Because they are plate or air quenched, the edge can be taken down to almost final dimensions. I have sent a few AEBL and CPM M4 blades to Peter's heat treating that had edges sub 0.010", and they came back perfect.

Back to carbon steel (I am assuming that is what you are using), I have found that the longer the blade, and the taller the blade, the thicker the edge needs to be in an oil quench. Long, tall, Santoku-like blades seem to have more edge distortion than shorter blades. Also, if you use a fast oil on a steel that doesn't need fast oil, like O1 or 52100, then there is more edge distortion.

Last edited by samuraistuart; 08-17-2018 at 12:32 PM.
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