What to do with 10mm thick O1 steel?

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AlexKV

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Jan 28, 2015
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So I'm new in knifemaking, but have been working with tools for many years. These days, I'll be getting a piece of flat stock of O1 tool steel which is 10mm thick, 80mm wide and 25cm long. That's a pretty thick flat bar for any knife, so it will have to get thinner by forging or grinding it, but.... As I've read, many knifemakers cut pieces of annealed tool steel with a hacksaw, but is it possible to cut a piece by it's thickness with a hacksaw with some higher quality blade?
I'm not scared even of few hours of work, but has anyone done something like that? I would be cutting out a piece of 40x200mm, and then, if it is possible, would cut that piece by it's thickness to get two pieces of 4mm thickness (let's say hacksaw blade eats out those 2mm in the middle).
Should I try it, or forget about it and go straight to hammer forging?
 
Yea I don't think attempting to cut down the thickness would be worth it...way better to forge to shape with that thickness. Wouldn't take too long at 10mm. Just remember with O1 to only forge while its red to orange (between 1600f and 1900f) otherwise you can damage the internal structure or get surface crazing along the blade. Happened to me a little while back with some O1...looks like spider web cracks along the surface of the steel.

Good luck with it ;)


Sent from my iPad using Tapatalk
 
^what Eric said lol
Yea making a width cut that small is probably going to end in a very uneven cut.
Not saying it's impossible but their isn't a world where I would try it unless life or limb depended on it ;)

Paul
 
If you are going to forge it, understand that it will probably harden enough to make it very difficult for manual work later. If you don't have the equipment to anneal it, plan everything out first. If you have machines that are able to cut, grind and drill hardened steel, there won't be a problem.

As already mentioned, O1 will partially harden if you aren't annealing it so temper it to be safe.
 
Okay, so all the votes go to forging :) ...and that's what it's going to be done. And I guess that slow cooling the forged piece in charcoal barbeque/forge, covered with bricks for slower cooling will make the steel softer than just letting it air-cool.
 
AlexKV said:
Okay, so all the votes go to forging :) ...and that's what it's going to be done. And I guess that slow cooling the forged piece in charcoal barbeque/forge, covered with bricks for slower cooling will make the steel softer than just letting it air-cool.
Click to expand...

From both my experience and calculations, yes and no. Yes, it will most likely be softer than HRC 45. No it won't be close to the softness as when you received it from your supplier (hopefully your supplier provides you with softened steel).

Just to give you an idea, I worked on a piece of O1 by hand. Purchased a flat bar and went straight to draw filing it. After I forged part of it, I left it inside the forge to cool down a bit and wrapped it with insulation (kaowool I think). A small portion of it was exposed as I did not have a large piece of kaowool.

The non exposed part was not very difficult to file. It got a bit harder but it isn't impossible to work with. The exposed part was much harder to file. Although the file bites into it, I could only remove about 1/10 of the usual volume per stroke.

Drilling through both was now no longer possible. I'm guessing the core hardened much more than the surface because as the heat comes to the surface, there is the auto tempering effect but once the core hardens up, there is no more heat to temper that.

Before forging, plan out what steps you need to take that does not involve forging! =)
 
O-1 needs an annealing after being worked.

If using a forge - Start by heating to just above non-magnetic (about 1400F). Hold there for a few minutes to assure full solution, then pull out and cool to just when it gets magnetic again ( about 1250F). Stick back in the forge and hold there for at least a few minutes. Try and keep it at just dull red. Cool in still air until it looses all color ( black heat at around 900F), and either let air cool to ambient, or water quench to cool down faster.

If a HT oven is available - Place in pre-heated oven at 1400F and hold for 5 minutes, reduce to 1250F and once it drops soak for 30 minutes to two hours. Shut off the oven and allow to slow cool to 950F. Once at 900-950F, either air cool or water quench.





One thing you could make out of that thick stock is a small camp "tool" that looks like a short blade survival hatchet with a slight curve to the handle.
This is only for a basic idea of what I an referring to ( ignore all the zombie serrations and spikes).
http://www.ebay.com/itm/10-TACTICAL...044949?hash=item2a652c8d15:g:b0AAAOSwJQdXCISi
 
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Yeah, the steel comes in fully annealed (soft) state. I've never worked with a tool steel yet so I don't know how soft it is for sawing and filing it.
A friend who works with tool steels (but never used O1) tried milling a surface of 80mm wide bar, to reduce the thickness, but when he released a piece from the mill vise, it just jumped out and bent like a leaf spring. He even tried more times with new pieces, with cooling solutions while milled, and same thing happen.
Will this happen to O1?
I was also thinking about cutting a piece from that wide bar to match the size of Fallkniven A1 Pro or S1 pro, and mill it to get to 7mm thickness, and then file the bevels...
And is it possible to file out the bevels and then remove the thickness with a file? It is possible, but is it practical?
 
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What equipment do you have? The community machine shop that I go to doesn't have a saw capable of cutting steel so I just cut mine by hand (hacksaw). Thickest was quarter inch. It will take some time and a lot of hard work to cut it but it's achievable as long as you are not trying to set a world record in getting it done.

If you need to round out a piece, make rough cuts to remove as much material as possible, then rough it against a stone.

I also hand filed a 28 inch sword. It does take some time but it isn't difficult. If you want a thinner knife, it would be practical to file the bevels slightly first and then file down the non beveled parts to reduce thickness. My opinion is that this is practical because the more pressure you apply to filing, the more material you can remove. If you start with the bevels, you aren't attacking the whole surface of the piece. Reduced area with the same applied force = more pressure = more material removed. After you finish that, you attack the flat part of the steel. With reduced area there, you can remove more material at once.

If you are going down the path of filing, get yourself a Nicholson file, a very good file card (unclog the steel bits from the file), a neodymium magnet, and a vacuum cleaner if you are indoors (you don't want to be stepping on that).

Do some geometry first to see what angle you need to bevel the blade.
 
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