O-1 Tool Steel

[greg Forster]

What is the hardness of O-1 from the supplier- in "raw" form

[David Weaver]

From a non-scientific standpoint of understanding, I don't think you're going to see a comparable rockwell number for annealed material because rockwell hardness testing isn't so great for softer materials.

Mcmaster expresses the hardness of the annealed material on the brinnel scale, and says 221. Wiki says brinnel for tool steel hardened is 1500-1600, which then disagrees with their conversion charts (which do say that 200 brinnel is somewhere around 20 rockwell, which would explain why there isn't a rockwell number given for the hardness).

For practical purposes, any decent file or hacksaw will cut annealed O1 easily, and at the same time, it is completely unsuitable for edge tool work without being hardened. It does make reasonably decent stock to work with for plane parts - it peins fine and you can comb cut it.

[george wilson]

What David has said is sufficient for your needs. It can be sawed,drilled,and filed in the condition it is supplied in.

[Paul Saffold]

What is "comb cut"?




It does make reasonably decent stock to work with for plane parts - it peins fine and you can comb cut it.

[James Taglienti]

it cuts easily with a plastic barbers comb.

[David Weaver]

Comb cut means you can take an area that you're going to waste, like between dovetails, and make saw kerfs in it leaving what look like comb teeth. You can then hit those comb teeth with a cold chisel and break them off. In O1, sometimes they have to go back and forth once or twice, but they'll break off.

If you have no power tools to work metal (and generally that's my case), you can lay out all of your marks and remove a lot of the metal that way. With a coarse tooth hacksaw, you can cut the kerfs pretty quickly, and then just knock the teeth with a cold chisel rather than trying to file out the waste.

[David Weaver]

See attached. Sorry I don't have any better pictures. This was my first plane (a little one), so I took pictures of what I was doing for a reason I can't remember, I think i had a thread on woodnet, but it's long gone and I'm persona non grata over there.

I've done two planes this way. I like working the metal, it's predictable, and then there's not a lot of filing. It is a lot of physical work on a thicker side and bottom, though.

176751


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[Paul Saffold]

Thanks David. I tried Googling it but all I got was barber related. Paul

[greg Forster]

Thanks everyone for the input. What I'm curious about is appox. how hard would the steel be if I don't heat treat it. I'm making a float and I'm afraid of warping with heat as the material is 3/32"

[george wilson]

The 01 is about 35 RC un hardened,if that does you any good. The important thing is that it can be worked with files,hacksaw,etc.

The float will certainly warp if you heat it up and quench it. This can be fixed,however. Sand off the back side of the float,and heat it up carefully to a dark brown color,or a blue color. WHILE IT IS HOT,catch the float between 2 substantial wooden dowels seated into a hardwood block. they should be about 1/2" apart. The hardwood block needs to be firmly clamped in a stout vise. While the float IS STILL HOT,you can stick it between the dowels and twist it back straight as can be,holding the tang with vise grip pliers. The steel will bend like crazy while hot without breaking. You MUST make sure the float is still hot while you are bending it. If needed,let it cool off,and sand the metal down again,and re heat it to brown or blue,and go back to bending it. If the float gets too cool while you are bending it,it will snap like glass.

I have used this trick many times to straighten half round reamers I made. They also warp badly when hardening due to the difference in surface area on each side. Anything with differing area on opposite sides,like a plane with a bevel ground upon it before hardening,will warp. Never grind a plane iron before hardening. You cannot straighten a plane iron warped across its width.

If you expect to be able to FILE the float sharp when it gets dull,I suggest tempering it to blue. It will be as hard as a saw blade. If you hardened it at too high a temperature,it may not be soft enough to file when tempered at blue. Use a magnet to test the steel when you are hardening it. When the magnet is no longer attracted to the steel,it is at hardening temp. Try to not ruin the magnet by getting it too hot. Check with it quickly while the steel is hot.

[Trevor Walsh]

James, your wit just never gets old. I love it.

[Steve knight]

it is soft when you get it unless you pay a big amount for hardened. it cuts like most steel though it is a bit harder.

[greg Forster]

Thanks, at about 35Rc, that is softer than I was hoping, so I will try heat treating.

[george wilson]

Actually,my memory was faulty. The 01 is more like 20 RC annealed. I usually don't worry about how hard it is as long as it can be sawn,milled,etc.. I only concern,and test for hardness AFTER heat treating.

[David Weaver]

I would definitely heat treat the float. If you make a plane and it's maple or something abrasive, and you're working the end grain with the floats, they'll wear the tips right off of unhardened O1.

O1 is pretty well behaved, it shouldn't warp that much.

George - don't file manufacturers have to do the exact process you mentioned because their files get all pooched up after heat treating? They roll them through rollers or something after they're quenced, but they're still maleable?

If someone doesn't have a good oven that will get hot enough, you can always temper a float with a torch and tempilsticks or color. It's not going to be consistent like a nice new piece of spring steel, but it'll be good enough, and far better than leaving the float unhardened.

Whatever you do, don't copy LN and buy S7 steel unless you're going to send it to a commercial heat treater. I have a small box of S7 now and nothing to do with it except maybe make a knife or two in the future and pay to have them heat treated.

[Ron Petley]

I made a few from these directions:
http://norsewoodsmith.com/content/pair-planemakers-floats

You can do it with a hack saw and a triangular file.
Then quench and HT and you should be good to go.
Great things to have around, and a fun project.
Cheers Ron.