How hard should my O-1 be?

L

Livens

Joined
Jun 2, 2009
Messages
4
Hi,

Im new here, very new. Ive been into woodworking for years, and have slowly started using more hand tools than power ones.

So I have a need for a hook/bent/spoon knife and decided I could just make one myself. After reading here, and many other places I decided to use O-1 steel. Mostly because I am hardening and tempering it myself and read that O-1 is the easiest for novice DIY'ers.

The knife is made from 3/32" X 1/2" ground flat stock. The bevel goes to almost 3/4 the width, thats the best way I can describe it. I used 2 propane torches aligned with each other to heat to cherry red, and a small magnet to test for that too. Quenched in mineral oil. I did a file test to see that it actaully hardened, it did. Then I put in it a 420°F preheated oven for an hour, then air cooled. Cleaned it up and started honing the blade... hours later Im still honing, using 300 grit wet/dry sandpaper on a hard flat surface for the back, and a large wooden dowel for the curved part. Ive honed my chisels with the wet/dry, going up to 800 grit, and it works great. But this seems to be taking alot longer than I expected.

My question is, was 420°F enough? I looked at this O-1 tempering graph:

http://www.navaching.com/forge/forge.gifs/tempero1.jpg

And IF things went right (big if), at 420°F I should be at around Rc61-62? For a carving blade this thin what is the optimum Rc? My plan was to temper again at ~460°F to get into the Rc58-59 range, but thought I would ask first.

Thanks for reading :)

Jeremy
 
Here is a link to some info on O1 HT, It sounds like you did not soak so you may not start at full hardness. 400 is usually good for a knife but this chart will help you see if thats were you want to be. Yes it is tough to sand O1 after hardening. I usually start with 220 and water to get close to where I need to be then go to 320. If you have belts cut one up and they will last alot longer than sand paper.

Post pics, have fun


http://nessteel.com/o-1tech2.htm
 
Thanks Patrick,

No, I did not soak. It really was not feasable for me to accuratly hold the blade at any one temp for too long with the torches so I didnt try it. I breifly contemplated building a small "brake drum forge" (gotta love youtube!) but I am prone to go overboard on things... so I decided that I did not really need professional results with this.

I think Ill hold off on softening it any more. I hone it down to 800-1000 grit and see how it cuts. Im assuming if it is too hard that the blade will be prone to chipping?

Ill post some pics when I can.

Thanks,

Jeremy
 
I dont think you are going to have a problem at 400f, I would not make the edge too thin keep to 0.04 and it should have enough beef to hold a edge and not worry about chipping. Sounds like you have a good knife. To do an edge manually (I use a grinder now), glue 2-3" wide strips of leather to a 2-3" wide board the same length as the sandpaper sheet. I use clips to hold the sandpaper on the board and draw the knife across just like using a sharpening stone. You can use anything for the pad, some use mouse pads.

If you start with 220 you can get to 1000 pretty quick. Use a little water with it.

For the next one get a few fire bricks like they use in kilns and set up into a little house, will save alot of propane. I have a propane torch connected to a large bottle. There are fittings available for that.
 
You must log in or register to reply here.
Back
Top