How do I un warp a blade with limited resources

M

montana guy

Joined
Dec 18, 2009
Messages
472
I am working on my second knife and all I have to harden the cutting edge is a cutting torch. I have access to a forge also. Those are my resources for heat. My blade when I went to harden the cutting edge today warped badly. I tried heating it back up and making it bend the other way a little to undo the warp but it did not work. Then I tried it again with making it bend the other way even further, it did get better but it is still warped. The blade is very thin and fairly long. It is 1095 and 01 Damascus folded 1584 times.

With it being so thin I do not think I would have enough metal left to remove more forge scale or hammer marks and I would be back to square one having to harden it again.

Maybe smash it between two bigger pieces of steel after it is heated leaving it clamped together until it cools? Hardening would be fubar then?

Or just deal with it...

The black area is worst part of the warp, sanded over it with sand paper wrapped around a file and that is the spot that the paper did not touch.
DSC00114.jpg


Thanks in advance.
Ronnie
 
The usual advice given is to start with a normalized blade first because they warp the least. And interrupt the quench once you're safely under the nose and straighten any kinks with gloved hands while the steel is still dead soft austenite.

You will be fighting an uphill battle because any quench fast enough to harden 1095 is going to be fairly drastic (perhaps too drastic for O1)
 
Thanks Nathan, did not think this would be easy.

It was normalized 3 times just because I wanted to be sure being new to knife making. It did not warp during the quenching to harden the whole blade just when I tried to make the cutting edge harder than it was. It was a rockwell 43 overall before I did the HT, 58 overall after the HT and the cutting edge is now 67. I am thinking I am going to have to undo all that to fix it....
 
You should probably normalize and try again. You could sandwich the steel between 2 plates of 1/8 inch steel. I would help to prevent some warpage but cooling rapidly enough would be an issue. If the blade was normalized properly, ground evenly, heated evenly and to the proper temp then plunged vertically it would probably not have warped. I did a 6" blade .1" thick blade at the ricasso with a distal taper to the point with the edge under .02". Heated it in the forge muffle with a thermocouple to hold at the proper temp. Made sure I went in straight and came out with zero warpage. The thickness of the blade is only a small part of the warp problem.
 
A C Richards said:
You should probably normalize and try again. You could sandwich the steel between 2 plates of 1/8 inch steel. I would help to prevent some warpage but cooling rapidly enough would be an issue. If the blade was normalized properly, ground evenly, heated evenly and to the proper temp then plunged vertically it would probably not have warped. I did a 6" blade .1" thick blade at the ricasso with a distal taper to the point with the edge under .02". Heated it in the forge muffle with a thermocouple to hold at the proper temp. Made sure I went in straight and came out with zero warpage. The thickness of the blade is only a small part of the warp problem.
Click to expand...

Everything you said was done except plunging it vertically. I only have a small thing I made that it drops into flat on it side. It is a 3/16 steel over sized bread pan more or less and thinking about it, it's coolness probably created the warp as the blade sits right on it....I need a shop where I can leave a bucket of oil unattended...lol

Thanks for the help.
Ronnie
 
If you are not going in edge or point first that is your problem The difference in cooling will cause a warp. If you are limited on space try using a pipe and go in tip first. This can reduce the footprint of the container you need. I think this should be your next purchase/fabrication. It will make life much easier. If you look at Bruce Bump's website I think he has a pipe quench tank. It does not have to be out of SS, schedule 40 pipe would work fine.
 
A C Richards said:
If you are not going in edge or point first that is your problem The difference in cooling will cause a warp. If you are limited on space try using a pipe and go in tip first. This can reduce the footprint of the container you need. I think this should be your next purchase/fabrication. It will make life much easier. If you look at Bruce Bump's website I think he has a pipe quench tank. It does not have to be out of SS, schedule 40 pipe would work fine.
Click to expand...

That is next, thanks for the idea.
 
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