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- Aug 13, 2022
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I kind of asked this question before but it was buried in another topic. when do you recommend to heat treat, after shaping and holes drilled, and primary grinds done before any grinding
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When to heat treat
- Thread starter panzerjunky
- Start date
I do most of the profiling before HT, bevels after. I tend to leave extra material at the tip and grind the shoulders on the tang just before making the handle. This is for hidden tang kitchen knives, mostly stainless steel. I ordered some steel to experiment with hamons and will partially grind the bevels before HT.
I think N Natlek does everything post HT, including drilling the holes using carbide masonry bits, IIRC.
I'm not sure if there is a good answer to your question, a lot will depend on the type of knife you are making, the steel you're using, the equipment you have available and your personal preferences. Generally, it seems that most kitchen knife makers working with thin stock do most of the bevel grinding after HT, and folks who make knives from thicker stock tend to partially grind bevels before HT.
I think N Natlek does everything post HT, including drilling the holes using carbide masonry bits, IIRC.
I'm not sure if there is a good answer to your question, a lot will depend on the type of knife you are making, the steel you're using, the equipment you have available and your personal preferences. Generally, it seems that most kitchen knife makers working with thin stock do most of the bevel grinding after HT, and folks who make knives from thicker stock tend to partially grind bevels before HT.
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The answer, as always, is: it depends.
When you grind the bevel before HT, they might not be equal on both sides, this cause the blade to warp
But if you grind after HT, the steel is much harder and it'll take much longer to grind, also you'll have to be extra careful about the heat.
Holes are almost always drilled before HT.
Personally, if I'm doing steels like M390, D2, ... I take them to 90% finish, for AEBL, 5160, ... I take them to 70-80% finish before HT. I don't mind warping that much.
When you grind the bevel before HT, they might not be equal on both sides, this cause the blade to warp
But if you grind after HT, the steel is much harder and it'll take much longer to grind, also you'll have to be extra careful about the heat.
Holes are almost always drilled before HT.
Personally, if I'm doing steels like M390, D2, ... I take them to 90% finish, for AEBL, 5160, ... I take them to 70-80% finish before HT. I don't mind warping that much.
- Joined
- Feb 16, 2022
- Messages
- 615
I do my profiling, and all the drilling first (obviously). Then heat treat and grind my bevels after. For my stock removal stuff. Especially since I use steels that I plate quench, and I want the best contact I can get. Minimizes warping (really completely eliminates it) . Allow me to get to hand hot so I can get it into the cooling bath as quickly as possible to continue cooling. Then grind, its slower grinding like this. but if I have a better chance of avoiding warps, and having a more consistent ht it's worth it for me.
If it's a forged blade. I forge, then normalize, anneal, do any drilling. Do some grinding to make sure the blade is consistently shaped. Then harden, and finish grinding.
If it's a forged blade. I forge, then normalize, anneal, do any drilling. Do some grinding to make sure the blade is consistently shaped. Then harden, and finish grinding.
Stuart Davenport Knives
Knifemaker / Craftsman / Service Provider
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- Feb 7, 2022
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- 455
I do basically what PMQ said. It really depends on the steel and the thickness of the stock I am working with. If it's like 0.100" and above, I will grind the bevels about 80% prior to HT . Any thinner than that, and I'll usually grind after heat treatment.
However, if the steel is very wear resistant, even if it's sub 1/8", I like to grind most of it prior to heat treatment.
Steels like AEBL are easy to grind in the hardened state. I find that jumping up to CPM 154CM or D2, it seems to be more difficult to grind hardened, and it makes sense because of the higher carbide volume over AEBL, even tho they are relatively soft chromium carbides. Especially steels like M4, 4V, M390, 10V, etc......those get about 80% bevels prior to HT.
However, if the steel is very wear resistant, even if it's sub 1/8", I like to grind most of it prior to heat treatment.
Steels like AEBL are easy to grind in the hardened state. I find that jumping up to CPM 154CM or D2, it seems to be more difficult to grind hardened, and it makes sense because of the higher carbide volume over AEBL, even tho they are relatively soft chromium carbides. Especially steels like M4, 4V, M390, 10V, etc......those get about 80% bevels prior to HT.
Not that I am that experienced at all, but I do HT after I've ground bevels and sanded to 120. I aim to have a consistent edge of about 0.035" or less. Then after ht its a quick 120 grind to take off any residue or minor scale and take edge to less than .02" for hand sanding. I'm using 80CRV2 and have done a couple recycled mower blades. I just found trying to grind after HT chews through belts to finish the grinding. So far been able to take any minor warp out after the temper using the three rod system in a vise and low heat to the spine.
I have only just finished knife #7 though, and in the process of profiling 8-11 but this is just what I have learned works for me. Knife 3 edge warped but the spine was still straight. Ended up taking about 1/2" off the end to get it straight as it was too brittle and I cracked/chipped the edge trying to straighten it while keeping it cold enough to not ruin the HT. Knife 4 I left at about 0.07 edge thickness at ht. It held straight, but was a huge pain to get it down to where I wanted prior to sharpening. 5 and 6 both turned out straight, and 7 had just a tiny warp near the end that I was able to straighten after temper. For me the risk of small warps is worth it to take the edge down so much prior to HT.
I have only just finished knife #7 though, and in the process of profiling 8-11 but this is just what I have learned works for me. Knife 3 edge warped but the spine was still straight. Ended up taking about 1/2" off the end to get it straight as it was too brittle and I cracked/chipped the edge trying to straighten it while keeping it cold enough to not ruin the HT. Knife 4 I left at about 0.07 edge thickness at ht. It held straight, but was a huge pain to get it down to where I wanted prior to sharpening. 5 and 6 both turned out straight, and 7 had just a tiny warp near the end that I was able to straighten after temper. For me the risk of small warps is worth it to take the edge down so much prior to HT.
Horsewright
Knifemaker / Craftsman / Service Provider
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- Oct 4, 2011
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- 13,337
I mainly work in two different steels, 26C3 and AEB-L. On the AEB-L blades are cut, profiled and drilled before HT and then all bevel grinding is done after HT. On the 26C3 I have ground bevels before and after heat treat. It grinds well post HT but I tend to get a lil better hamon if I grind bevels prior to HT. Just finished off a 109 blades yesterday in 26C3. Clay is drying and they'll ship out tomorrow.