Stock Removal Files and Rasps

J

John Hoe Handle

Joined
May 3, 2017
Messages
22
I have forged a few knives out of 1084. All has their warts but overall satisfied.

I have never made a stock removal knife. If a guy does not care about going thru belts, can you just grind out a Nicholson file without annealing, and not have to worry about quenching? And temper to desired hardness?

I think I know the answer, because I grinded off the teeth of the file and that took forever with a 36 grit belt. Still see the teeth in some spots. Didn't even get to beveling yet.
 
Try a sub-critical anneal , 1200 F for two hours - no scale ,no decarb , easy.
 
If you don't have a HT oven to do a sub-critical anneal, this will work:

Heat to bright red - around 1800F
let cool until black
Heat to medium cherry red - around 1600F
let cool to black
Heat to red - between 1300 and 1400
let cool to black
heat to just barely glowing red - between 1000 and 1200
let cool to black
repeat barely red
let cool to room temp.

The file should be soft and have good grain structure for grinding into a knife. Do the HT as if it was 1095/W2.
 
Interesting. Never heard of that technique. I will give it a try. I am going to take some of these old files and heat em to past critical and put in a charcoal grill full of lit charcoal, and let it burn itself out first.
 
I have been told by some well known knife and sword makers who are also metallurgists that it is not a good idea to do that type of anneal on a file (or hyper-eutectoid steel). If I understand your comment, you are trying to anneal the file by letting it cool in charcoal, allowing the temp of the file to drop as the temp of the charcoal drops. This will soften it, but the resulting microstructure is not ideal for hypereutectoids steels, of which files are commonly made from...like 1095, w1, w2, etc. Any cooling slower than still air will place the pro-eutectoid cementite carbides into the grain boundary, which if not dealt with later (normalizing), will result in a blade that is more brittle than it should be after hardening. While that style of anneal will soften a file enough to grind/file, it may or may not work all that well when it comes to drilling, as you essentially have a lamellar anneal (layers of hard, layers of soft). The best way to anneal a file is the sub-critical spheroidizing anneal that "Mete" (our resident metallurgist) mentioned, and if not possible...Stacy also gave excellent advice for an anneal.

When I was new to knife making, I did the exact same thing you did. Wanted to anneal a file, so I got the Weber grill fired up, heated file past critical temp (magnet check!), and allowed the file to cool with the charcoal. I did not have a rack for the file to rest in, simply placed it in the coals. Next morning, my file had a bow in it...the exact same curve as the bottom of that Weber grill! (funny how that worked that way!) If you do go that route...suspend the file somehow. Use the grate as a rack rest, as long as the fire doesn't get so hot it bends the grate, too!
 
While the metallurgical method I posted sounds complex, it can be done with a torch or forge and takes about 5 minutes to do. It will yield pearlitic steel with a fine grain.
 
I have done two stock removal knives out of files, no anneal or heat treat, I did the bulk of the removal with an angle grinder and bench grinder (this was before I bought my 1x30 sander). I was sure to water cool often using the grinders. Took about 4-6 hours to get them rough ground to shape and thinned. It would have been faster if I had my belt sander. They definitely hold an edge.
 
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