How Hard Can O-1 Steel Get?

[Tom LaRussa]

In case anybody's wondering...

I hardened my first plane blade about a week ago.

I ground the blade from 1/4" thick Starrett O-1 steel purchased from Enco. http://www.use-enco.com (http://www.use-enco.com/) (They have really good prices on this stuff.)

I heated the blade in my BBQ until a magnet would no longer stick to it, then quenched it in a mixture of salad and olive oils. (For you fellow foodies out there -- don't worry, it was low-grade "lite" olive oil that somebody left at my house. Not really fit for human consumption.)

When it was cool I washed it, and tempered by putting it into a cold oven which I then set to 325 degrees (F). I left it in there for an hour before turning off the heat and letting it cool down for several hours before opening the oven door.

Note: The 325 temp was suggested by Ron Hock -- http://www.hocktools.com/diyht.htm -- and the hour was just a guess.

Okay, so that's how I made the blade.

Lately I've been playing around with plane designs, and I decided that I needed to drill a hole in this home-made plane blade. So I chucked a 5/16" (supposedly) HSS in my drill press and went at it.

When that didn't work I tried another drill bit.

Then another.

Final score:

Three nicely rounded, very blue, drill bits.:o

One very small dimple in the plane blade. :p

Pic below. Note: The blade in the pic measures just under 2" across.

[Tyler Howell]

Very interesting.

Excellent Tom, As a member of the Pix Police I'd like to give an honorable mention on your outstanding performance of late. There has been a continuous flow of great projects and visual record of said projects. Truly a stellar effort and inspiration to others.

The Pix Police salutes you!!;)

[Tom LaRussa]

Very interesting.

Excellent Tom, As a member of the Pix Police I'd like to give an honorable mention on your outstanding performance of late. There has been a continuous flow of great projects and visual record of said projects. Truly a stellar effort and inspiration to others.

The Pix Police salutes you!!;)
Thanks Tyler!

It's truly an honor to be recognized by the GPPP himself. :D

Note: GPPP = Grand Poobah of the Pix Police ;) :p

[Pam Niedermayer]

Cool. Next time you might want to try a punch, before hardening, rather than a drill.

Pam

[Tom LaRussa]

Cool. Next time you might want to try a punch, before hardening, rather than a drill.

Pam
Pam,

When you say try a punch, do you mean the kind you hit with a hammer?

I was thinking I should have just drilled it before hardening it.

[Tim Sproul]

And grind a bevel too! The pic looks like a rectangular blank. ....that is, grind a bevel before hardening.

IIRC, O-1 tool steel can be hardened to Rc62.

[Jim Dye]

Dont know if it will work. But try a cobalt drill bit, they are for drilling harder metals. Should have them at any hardware store. Also keep the drill cool by using oil.

[Ray Thompson]

I've seen 01 up in the Rc 64-66 range but it wasn't much good, way to brittle. By that I mean it will sharpen very well but the edge will probably chip easily.

Tempering at 325 will give you a hardness of about Rc 62. I think my preference would be about 450 degrees giving a hardness of about Rc 57-59. Best thing to do is experiment.

If you are heating in a BBQ grill I think I would inject some air with some kind of small fan. More oxygen = more heat. For 01 you want to get up to about 1500 before quenching.

Ray

[Tom LaRussa]

And grind a bevel too! The pic looks like a rectangular blank. ....that is, grind a bevel before hardening.
That's the back side.

The bevel is on the other side.

:D

[Pam Niedermayer]

Pam,

When you say try a punch, do you mean the kind you hit with a hammer?

I was thinking I should have just drilled it before hardening it.


Yes and yes.