I accidently overheated my finished blade – pls your help

S

Steinmann

Joined
Jan 12, 2010
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99
While trying to fix/grind something on the folder's blade, I noticed a color change on 2 spots along the cutting edge. Unfortunately - the blade is already penned to the scales (friction folder). I would like to know if it is possible to heat treat the cutting edge alone, while I will keep the handle/scales in a water bucket? If ok – how do you guys think I should do this process? The blade is an old Nicholson file. I have a torch and was thinking to red cherry the blade, dip in warmed veggie oil and then a few passes with the torch again until gold brown.
Any help will be much appreciated – thank you.
 
First, that HT won't work.

Second, what "color changes" did you see? If you slightly blued the edge, it may be a bit softer in that area, but you can finish out the blade and it should be OK. If you turned it red while grinding, the only solution would be to take the knife apart and re-do the HT. If the edge is already ground, that would probably have its own problems with warp.

Probably best to just finish this one and see how it does.
 
Richardlittle said:
As long as you did not quench it when it got hot and just let it cool down naturaly I do not see why you need to do anything. Now if you quenched it you made it brittle and you need to normalize it but it should of normalized on natural cool down. Just polish out any mis-coloration.

My statement is not fact just what I am thinking at the time.
Click to expand...

Amen to that :D
 
The OP only heated the blade into the tempering range, not to critical. That would make make the blade softer where it was overheated but quenching it in water would have no effect. If he had heated it past critical(not possible on a belt grinder) and quenched it then yes, it would be hardened and brittle but taking a torch to it and heating it to red again would make it far to soft to use a knife blade.
 
Richard,
You really need to read up on metallurgy. Nothing in that reply applies to this situation, and your conclusions are not correct..
 
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