Getting mixed answers on annealing and file knife.

Triought

Triought

Joined
Jul 18, 2014
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So for my 3rd knife I thought I'd try some old antique files I got gave to me. They are stamped made in the USA and I broke one on the vice to test.

So I know you need to heat the file up before grinding to make it softer. I've been told by some to just heat it in the oven at 450 to soften it, I've been told to heat it to black (just before it glows), then I've been told to heat it til it's red and then let it air cool.

I'm willing to test these out but I thought it may be best just to ask and get a complete answer. I have a home made firebrick forge I made and I have a oven in the shop now. So I can accomplish any method needed just curious on the route to take.
 
Many answers will work, though what will work best for you? Old files, I hammer, though usually only for "shop" knives. Customers get virgin steel. Anyway...

Tempering it back to soften to knife territory will avoid re -heat treating. 450 is assuming it is a 10XX steel most likely, and is a decent bet. "Black" heat could very well be a good anneal to make it softer and easier to grind, but will require re-hardening and tempering. Red heat could anneal some depending on how slowly it is cooled. It can still air harden somewhat unless cooled very slowly. What sounds like it's worth a try to you?

Any more questions fire away. We all have answers and someone will have YOUR answer.
 
Heating the file to bright red and then letting it cool very slowly will give you almost the easiest to cold work steel. It will be easier to work than the other 2 methods you describe. You will need to heat to bright red and quench your blade before finishing.

Tempering the file back by heating to 450 F for an hour will result in maintaining the fine grain of the original file. But the file is still plenty hard. It will take you longer to grind a knife blade out of the file. When you are finished shaping the blade, all you need to do is put a handle on it and it is finished.

Heating to black red will soften the file quite a bit and make it easier to cold work than just drawing back the temper, but you will need to heat to bright red and quench before finishing. I don't see any real purpose to this method unless you didn't have the equipment available to do the first procedure at the moment.
 
Okay I think I get it now, thanks guys! With getting three different responses on how to do it I wasn't sure. Having it explained why you'd take each route makes a lot more sense. I'm going to go with the first route. Put the forge to use! Thanks!
 
Chris Lambeth said:
Many answers will work, though what will work best for you? Old files, I hammer, though usually only for "shop" knives. Customers get virgin steel. Anyway...

Tempering it back to soften to knife territory will avoid re -heat treating. 450 is assuming it is a 10XX steel most likely, and is a decent bet. "Black" heat could very well be a good anneal to make it softer and easier to grind, but will require re-hardening and tempering. Red heat could anneal some depending on how slowly it is cooled. It can still air harden somewhat unless cooled very slowly. What sounds like it's worth a try to you?

Any more questions fire away. We all have answers and someone will have YOUR answer.
Click to expand...

Thanks, yeah this is my third knife, right now I'm trying to find out what works for me and what doesn't. As well as increase my skill and craftsmanship. I have no plans on selling any of these first batches of various knives I'm making.
 
hahaha I never intended on making a second knife, let alone selling any. My intentions were discarded by fate. Now I can't even keep the ones I make for myself. Someone always offers...
 
Chris Lambeth said:
hahaha I never intended on making a second knife, let alone selling any. My intentions were discarded by fate. Now I can't even keep the ones I make for myself. Someone always offers...
Click to expand...

Crazy enough I just saw you were from Winston-Salem, NC area. I went to some football games up there. I help run a site called d2football and Winston-Salem was in the NC game a couple years ago.
 
Pretty much all you need to know is in the link that Salty posted.
I get asked about once a week how to make a knife out of a file, and the very simplest way is to take a Nicholson file and heat to 450, then grind the outline and bevels without over heating and wrap the handle with leather or cord.
You can usually drill handle pin holes with a carbide bit (and some patience), but there's nothing wrong with a wrapped handle.
The other approaches you mention have to do with doing your own complete heat treat process, from hard to soft to hard again and then tempered to just right. Again, it's all in the Count's writeup!
Have fun!
 
elementfe said:
Pretty much all you need to know is in the link that Salty posted.
I get asked about once a week how to make a knife out of a file, and the very simplest way is to take a Nicholson file and heat to 450, then grind the outline and bevels without over heating and wrap the handle with leather or cord.
You can usually drill handle pin holes with a carbide bit (and some patience), but there's nothing wrong with a wrapped handle.
The other approaches you mention have to do with doing your own complete heat treat process, from hard to soft to hard again and then tempered to just right. Again, it's all in the Count's writeup!
Have fun!
Click to expand...

Thanks, my first two knives I made out of 440C stainless, I just had a file and thought it'd be a fun thing to try since it seems to be a rite of passage almost. I just had 3 people telling me 3 different ways to do it.
 
To temper a file you can do a subcritical anneal at 1200 F for about 2 hours .This changes the martensite to spheroidized carbide in ferrite.
 
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