Any suggestions on hardening a double edge blade

D

Doc Hollywood

Joined
Jan 24, 2003
Messages
341
What I have working is a double edged cable damascus blade, with some old high speed steel drill bits welded to the cutting edge.

I guess I shoudl go into more detail here so. I have the blade shaped, and I took some old drill bits I had and forged them out flat. I bent these over to about 90 degreees at teh length, and forge welded them to the cutting edge all the way to the point. I have the blade shaped, and am to the point of heat treat (still have to anneal the whole thing, but).

How do you guys suggest I harden this thing and still leave the center relatively soft without warping the crap out of alot of work?

Doc
 
I've never done one but I would suppose some Satanite or Demon would be what I would use. If you got it on even enough. I've used the Demon on single edged blades and got no warpage. I put mine on and let dry for a couple of days. Then take a worn rasp and knock of the high spots on the Demon. Good luck and show pictures:)
 
Doc,
You mention something that's been going through my head for some time... There always is clay hardening, but I don't know how it works on double edges. Beyond that, I have a few ideas I haven't tested yet, but will soon. Who knows, one might work for you....

1. Create a pair of tongs with long jaws made of 1/4 or 1/2 inch rebar. Fully harden the blade then heat the tongs red and clamp the jaws down on the center of the blade to transfer the heat into the blade center first. Again, I'm not sure on this one, you may need a fan or water mist or something to keep the edge from heating too much.

2. A water over oil quench where you heat the entire blade, point it north, and quench it keeping it parrallel with the ground for a bit, then bringing it out of the quench for a bit, then back in keeping it parrallel. What I'm thinking of here is hardening the edge, but not leaving the blade in the quench long enough for the center to harden....


Again, these are completely untested ideas that I plan to try one of these days. I would suspect that normalizing 3 times is definitely in order....


Tim
 
Doc I would heat the entire blade in a forge and quench it point down just when the edges get nonmagnetic (very little soak time) The center will not be at critical that way but the edges and all surfaces will be. Damascus looks best if the whole thing is hardened. If you want to fool with a temperline you can clay coat the center mass first. Good Luck. Show us the results.
 
you could water tub it.
it's what I do. I made a special
one just for the double edge blades.

1 full heat quench
2 temper
3 then water tube it
drawing the center out as soft as you want it.
 
Since Bruce pointed out what I had not thought about (damascus looking nicer when the whole thing is harder), I guess I will follow the suggestions I have seen here.

I had an idea on tempering the thing that involved clay, and the method I recall from the 50 dollar knife shop. You guys who have read it will remember the one brick forge and tempering jig he described there. I am thinking I can make up the jig so I can heat the edge area, with the jig made int he same shape as the blade, and slightly smaller (to get into the thicker meat). If I am careful I should be able to temper carefully enough to temper the whole thing.

I still have questions on that idea, and the rebar tongs idea is sounding good too.

I got the idea for the high speed drill bit welding from a hammerin I attended at Batson Forge many years ago. There was an older fellow there (I guess in his 70's) that most of the others referred to as the "Junk Man". He showed alot of his stuff there, and his side carrier, which had the drill bits welded into the edge of the blade. The temper line ws gorgeous, and the offset material made the edges just jump right off the blade.

I will purchase a membership when I get this to the point of closer to finished so I can post pics, but I am not showing anyone this one till I am sure I won't ruin it.

I just picked up some nice big diameter cable from a freind recently, and swords will be coming soon. Jeez, I gotta hurry up and get my building finished.

Doc
 
http://www.dfoggknives.com/wuwei.htm

It can be done, but be extra careful. There is alot of room for error. Normalising is a must. Make sure your clay coating is even on both sides of the blade. I would suggest practicing on a few non-damascus blades first until you are comfortable.
 
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