farrier file

percy

Well-Known Member
my son has a customer that wants a few knives made from farrier files. He annealed them but we can't seem to get them hard enough for a good usable knife. Around 54 is the hardest we can get.
Can anyone give me info on heat treatment with a furnace temps and all to get this done.
You guys have always come up with the answers for me and I hope you can now.

Percy Richardson
The Knife Shop
 

J. Doyle

Dealer - Purveyor
Hi Percy. Unfortunately, they may be case hardened junk steel to start with.

If you think they are decent steel and hardening some though, you may try bumping up the temps 25 degrees from what you have been using.

What temps are you using and what are you quenching them in? That may be part of the issue.

I would think, generally speaking, 1475-1500 for 5 or 10 minutes and quenching in brine would tell you if there's any potential for decent blades.

There's too many unknowns and too much guess work for me to want to mess with these any more. Best of luck to you though.
 

Kentucky

Well-Known Member
Now farrier rasps are considered a consumable. They don't have to be that hard really. A few are still made from quality steel, many are not. I saw the specs on one new brand and they were made from .38% carbon steel.
 

Warren Krywko

Well-Known Member
If you want to know for sure, try 1550-1600f, then quench in brine. If it has 0.5% carbon or a bit more, you will get the max out of it that way, but you risk cracking it. Hypo euctoids need more heat and a faster quench than euctoids, or hypereuctoids.
 

CMS3900

Well-Known Member
Hello folks, I hope this thread is not old enough to warrant me starting a new one but I am having a similar issue.

I am currently trying to HT a rasp knife using a old Willie-Charlie rasp. My research indicates its from the 40's or 50's and should of been made of decent steel. I saved all of the chunks of extra material to practice my HT. The first piece was ramp to 1450, hold for 15, oil quench with oil heated to 150. I took the sample and put it in the vice and wacked it, and it bent over. Second piece was ramp to 1475, hold for 15, oil quench in same oil. Wacked that piece and had the same results. I took those chunks in and hardness tested them and it was sub-20. Switching assumptions I took another piece, ramped to 1450, soaked for 15, and then quenched in water. Wacked it and it snapped right off. Good results until I hardness tested it and it was all over the place depending on where and what side was tested from 35-55. The last test I did today was to put one more piece in and ramp to 1450 and soak for 30, thinking that it was possible I did not have a enough soak time for the conversion but I want to hit it on the surface grinder tomorrow and clean it up to see if it makes a difference.

The customer called for a hollow-ground skinner out of a file, otherwise I would be using O-1 or something known. I did explain to them at the time that the metallurgy of the rasp would be the deciding factor of its performance and they accepted that fact in order to get the "rasp look" they wanted. I know hawks are commonly hardened to a lower HRC and have decent edge retention and cutting ability, and people make camp knives out of 4140 which does not HT to very high hardness either. I guess what I am wondering is should I invest in some new rasps like Nicholson, Bellota, or Heller in the hopes of better (known) metallurgy, or just work to achieve the best HT with my samples and hope that 45-55 HRC gets the job done? I know the HRC will change post-tempering but I am unsure how much. I wouldn't think it would get harder.

Thanks,
Morgan
 
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Warren Krywko

Well-Known Member
While many think old = good steel, WWII used a lot of steel, making good steel harder to come by in the 40's. I'm no expert on files and rasps, but there is great variability in the steel from the little I know. You might want to try 1550, or even 1600 quenched in brine. If they are lower carbon, this may work. Woodworking tools don't need the same hardness that steel working tools do, so they can be lower carbon than steel working tools.
 
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