Wooops!

[Andrew Garrett]

Well, I warped my first blade tonight.

I imagine I did two things wrong. First, I ground too close to finished thickness on the bevels. I did not check for warpage after the olive oil quench, but did not notice any when I file tested my blade (1095 btw).

I tempered for an hour at 450F. Then, while the blade was still piping hot, I brought it back to the shop to cool. It didn't even occur to me at the time that I sat it right in front of a running box fan!

I noticed the warpage (at the tip) as soon as I picked it up. It's not real bad, but bad enough. I went back to the books and did some reading on fixing this. I tried the hammer on leather-topped-anvil method. I was very tender with my thin hard blade. It helped a little--say 40% fixed.

I then re-tempered at 300F for another hour and had to come to work. I'm planning on some more hammering tomorrow. Should I try something else instead?

Andy

[Ray Rogers]

I wouldn't hammer on a cold blade like that. Even if it straightens the blade it will induce stress in the steel that will create plenty of potential for failure later.

I would temper at 450 again (since that's what you initially used). As soon as the blade comes out of the oven straighten in a vise or arbor press using the 3 round rod set up. Much more control this way than with a hammer. You have about 30 seconds when the blade is at that temp that the steel will move fairly easily so work quickly and don't apply too much force .....

[AwP]

I'm guessing the warp was there from the quench and you just didn't notice it at first when it was scaley. Personally I'd straighten it at forging heat, normalize and re-HT. I don't think cooling from the temper by a fan really matters, tempering temps aren't really hot enough for cooling method to matter much, I usually quench in water from tempering and have never had any problems with it. You could try straightening it Ray's way, alot of knifemakers do it his way, but it just makes me nervous.

[Ray Rogers]

I agree that straightening from forging heat and re-doing the heat treat is a surer and safer way to do it but I was trying to avoid the extra work. Besides, once he does the quench again he may introduce some slight warpage again just as he did the first time. Sooner or later, being able to straighten a blade at lower temperatures will come in handy. However, this method is only good when the warpage is slight. For more extreme warpage I would follow AwP's method.....

[Andrew Garrett]

Well, I attemptemted the fix before I got any replies on this. "Snap". I did use the three pin in the vise method, I found in W. Goddard's book. He didn't mention heating it first. It snapped pretty easy too. I'm thinking I may need to triple draw these old 1095 Nicholson file knives I make.

That's it Ray. Time for you to write a book! A lot a of authors visit the mountains for the peace it allows when they write. You already live there, so...., get to it!

Thanks anyway fellas. I was real excited about this one too. Oh well, it's just a tip break, so I'll grind out a tanto tip and slap some old Diamondwood on for a handle. Should make a handy shop knife.

Another lesson learned (albiet the hard way).

Andy

[tmiller5087]

Yes Ray, that is a great Idea about you writing a book. I know your web site is informative and very entertaining. I think you would write a fine book that sells well.