Should I forge M390 super steel? Or stock remove only?

S

Smurf masher

Well-Known Member
I've bought a load of it. And it's 2.5mm thick. I think I could easily cut to chape with a saw, and then stock remove to get the right shape.

But... part of me wants to cut to the shape below then extend out the blade with a hammer and forge, bulk up the bolster, and shape the blade curve. That's my artistic side... my scientific side is screaming that this steel is created layer by layer to get the perfect grain, and heating it up and wacking it may revert this super steel to something less "super"

Or... would forging around the blade edge actually work harden it and make it even tougher? I'm airing towards just stock removal for these kitchen knives. Bu I do want to add some blacksmithing if I can to add the taper and the shape if I can without destroying the steel, and also so I can reduce waste as this steel is expensive.

If I can cut to these shapes I could basically avoid any wastage.

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I guess I don’t know your skill level as a smith. If you have the tools, and skills, then ya, it can be forged. It’s not going to make it better, and it’s going to be very, very difficult to work with a hammer. Closest thing to M390 that I have forged was ATS34, just to try it. It was not fun at all. I wouldn’t recommend it. If you really want to, I would just cut out one blank and try it.
 
Edwardshandmadeknives said:
I guess I don’t know your skill level as a smith. If you have the tools, and skills, then ya, it can be forged. It’s not going to make it better, and it’s going to be very, very difficult to work with a hammer. Closest thing to M390 that I have forged was ATS34, just to try it. It was not fun at all. I wouldn’t recommend it. If you really want to, I would just cut out one blank and try it.
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OK thank you. Main thing was to know if forging damaged the steel. I'll try both, but yeah.. I think I'm gonna be just cutting to shape then stock removing for the majority of the stainless knives. If I get my rolling mill sorted it might work, but then the taper will be tricky...

I bought a off cut from bohler direct at a great price, I should be able to make about 40 large knives out of it (probably only 30 if I stock remove). I'm sure after hammering for 4 hours per knife, i'll be grinding rather than hammering. (Fat cat for size reference)
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Thanks!
 
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I'm not familiar with this steel at all so take this with a very large grain of salt. When I ventured into the World of SS I asked a similar question about AEB-L. There was a Master Smith on here that contacted me via message telling me he had forged SS but now only did stock removal on SS. Told me that SS was very finicky and the working temp window was very small! To hot it would be damaged to cold it would crack! When you have a Master Smith tell you that I'm not gonna reinvent the wheel! I do all stock removal on it! Again this was for AEB-L but he made no distinction between any if the SS out there.
 
Gliden07 said:
I'm not familiar with this steel at all so take this with a very large grain of salt. When I ventured into the World of SS I asked a similar question about AEB-L. There was a Master Smith on here that contacted me via message telling me he had forged SS but now only did stock removal on SS. Told me that SS was very finicky and the working temp window was very small! To hot it would be damaged to cold it would crack! When you have a Master Smith tell you that I'm not gonna reinvent the wheel! I do all stock removal on it! Again this was for AEB-L but he made no distinction between any if the SS out there.
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Thank you. Going by the feedback i could waste 10 hours trying to bulk up a bolster and get the shape hammered out, and end up with a knife that has numerous possible invisible flaws in it, unless I do it all at a serious level of scientific accuracy.

I do have PID controlled kiln, but I think with this stuff i'll put my effort into handles and the finishing, and even outsource the heat treatment.
 
I forged a bowie by hand out of 440C once. That was enough. Try forging it, once, even if you go the stock removal route. It is worth experiencing the difference vs plain carbon.
 
2.5mm is only roughly .098 thick. Not anywhere thick enough to draw. Most smiths recommend .250 or thicker to start with.
I suppose with a great deal of skill it could be done, But I suspect by the time your done it would be so thin it would be nearly worthless.
 
Kev said:
2.5mm is only roughly .098 thick. Not anywhere thick enough to draw. Most smiths recommend .250 or thicker to start with.
I suppose with a great deal of skill it could be done, But I suspect by the time your done it would be so thin it would be nearly worthless.
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Well.. It's tight.. I wouldnt be moving the steel much.. narrowing the spine from 2.5mm to about 1mm at the tip.
My first knife, I managed to get a nice taper from 2.5mm to 1mm mostly via forging. (only about 30 minutes on the grinder to clean it up)
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But I might be able to get say an extra 5th on the blade length and say another cm on the cutting edge. It depends how badly it scales up I guess, and if I can get that (lucky) accurate the next time I try. I wouldn't need much... just enough to get the curve so I would not need to cut a curve. M390 is supposed to be tough enough to get away with very thin kitchen knife blades. (I was also very lucky it didn't warp at all when tempering or quenching)

So as close to this transformation I can get.
1656271185958.pngBut yeah.. I'm coming to the same conclusion as everyone here who has kindly posted. It's too thin, and too much hassle for little reward (and a lot that can go wrong) with these margins and this material. And bloody hard... I'd need to be .1mm accurate with every hit, not have much scale, and.. and.. etc...

But I also have a 5mm thick bit of elmax, and some AEB-L so the question was really to cover all stainless steels that are high grade.. better to forge, or better to stock remove, and I think.. thanks to you all that question is answered.
 
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Smurf masher said:
Thank you. Going by the feedback i could waste 10 hours trying to bulk up a bolster and get the shape hammered out, and end up with a knife that has numerous possible invisible flaws in it, unless I do it all at a serious level of scientific accuracy.

I do have PID controlled kiln, but I think with this stuff i'll put my effort into handles and the finishing, and even outsource the heat treatment.
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I’m guessing that there would be plenty of visible flaws too;) Air hardening steels don’t like to be forged. There are those that do it, so it can be done.
 
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