File knives

Dec 4, 2002
What do you think about file knives? pros cons etc...

I bought several Anza knives they look good (to me) sharpen easy appear as if they will last for many years. I have had some feedback on Anza but my question is really file knives in general.
I haven't had personal experience with any file knives other
than Anza, but I think those are terrific value.

Very strong knives that sharpen up real nice,
also they develop a good patina.
I've beaten on an Anza for 15 years, if it get's dinged up, I can clean it up with minimal effort.

They sharpen easily and take a scary edge.

They're carbon steel, so need to be oiled regularly. Other than that I haven't had any issues.

Go beat it up !!
File blades and carbon steel are superior in edge sharpeness to ordinary stainless. But be extremely careful not to pry with a carbon blade of any kind. They will snap, and break into (3) pieces sending one pc flying as a projectile. Also, as mentioned file blades must be kept oiled to prevent tarnishing and oxidation (rust corrosion).
I understand that Anza does a treatment on theirs to make them less brittle. Is that common with other makers as well and does it work? If so how?
I have been pretty happy with a knife I made from a file. I just cut the tip to make a sheeps foot point and ground the rest with a lot of time and frequent cools in water. I did some tests on it when I finished, just to see what it would take. I beat on it with a hammer, cranked it half way into a 3/16 brass rod, and generally abused it, but it hasnt broken. I havent used it in a while, and need to redo the handle, but its still in one piece. I even dropped it point first on the sidewalk (by accident) and it didnt break the point. It does have some rust spots, but thats to be expected. FYI, I made a point of not softening it before doing these tests, and the last time I tested it, during the grinding process, it checked at a 64 HRc.
File blades and carbon steel are superior in edge sharpeness to ordinary stainless. But be extremely careful not to pry with a carbon blade of any kind. They will snap, and break into (3) pieces sending one pc flying as a projectile.
That's a rather spurious generalization. As if stainless steel would do better, of course ;)?
Depends on the brittleness of the carbon molecular structure doesn't it? -- determined by heat treat and composition of the steel, stainless or non-stainless... since almost all steel has carbon in it.

Note: some files may have TOO much carbon in it to make for tough knives, and may chip and fracture easily - depending on the heat treat. However, in general, one shouldn't be prying with a knife anyway, so the lack of toughness may be irrelevant.
hi,what kind of steel are the files made from,i mean i like to make one,even bought a 1$ file from a boot sale but i dont know how to heat treat it?
Different brands of files are made different ways. Some are soft in the middle and hardened only on the outside surface. Some are hardened all the way through. These are generally a 1.00 % plain carbon steel, give or take a little on the carbon %. These are the kind to make a knife from. Nicholson Black Diamond files are generally regarded as the most reliable for use as a knife. If you want to see which kind you have, try to cut part way through then break off the piece with a hammer or lever it in a vice. Be sure to observe safety precautions and use protective equipment. A fully hardened one will break cleanly at the notch/cut, while a case hardened one (soft center, hard outside) will show some bending at the softer parts. Note that breaking cleanly does not always mean breaking easily. Mine had to be cut nearly 90% of the way through before I could break it with a claw hammer. I made the cuts with the abrasive cut-off wheels on a Dremel. This test should not be done at the tang, as the tang is generally soft, no matter what kind of file. You dont have to heat treat it, as long as you dont heat it during grinding/shaping. If you grind it hardened, expect frequent cools in water or something, or find a wet grinder. Grinding hardened steel takes a lot longer.

If you want to soften it first, use a propane, mapp gas or oxyacetylene torch and heat it to a red color and allow it to air cool. This will allow you to us a hacksaw to shape it and a drill press to drill it with regular bits. After shaping is done, you can heat the blade to the point it becomes non-magnetic, or a little hotter, then quench in oil, or water. Water will cool quickest and give a higher hardness, but may crack the blade. Oil may not harden it as high, but wont crack it, IME, but may warp it. After quenching to room temperature, leave the blade in the freezer for an hour. Then draw it in the kitchen oven at 325-375, the lower the temperature, the harder the blade. I repeated the freeze/oven cycle once more, but this may not be neccesary.

All this information is just for starters. If you try it and find you like making knives, then the heat treating of even plain carbon steels can become pretty involved. The shoptalk forum under "Makers" here on BladeForums gets to be pretty helpful.
Nicholson Black Diamond files were my favorite for making file knives. I did it a little differently though. I wanted to take some of the hardness out of the file/blade prior to grinding for a couple of reasons.

1) I baked the file at 325-350 degrees F for three hours. Took it out, let it cool to room temp and did another cycle in the oven. This brings the hardness down to roughly 59-60Rc.

2) The already tempered file was much easier and quicker to grind down than the fully hardened file. It also ate up fewer belts too. You still need to quench the file after every pass or two on the grinder in water to keep it cool from the grinding. Do NOT linger in one spot when grinding or you will overheat that spot and it will be much softer on that spot. You don't want this to happen.

3) When you've ground away everything that doesn't look like a knife, you can do a soft back draw at this point, if you so desire. I would put the knife edge down into icy cold water and take the torch to the spine of the knife. The knife should be submerged about half-way up the width of the blade into the water. As the spine heats up it will turn to a bluish-green color. When the spine begins to change color you need to walk the torch down toward the tip of the knife. This takes that spine portion down to a spring temper. The part that is in the water is protected from the heat so it keeps it's 59-60Rc. If the spine turns gray you've pretty much taken all of the hardness out of the spine and it is near dead-soft. This is not desirable for my uses. I want the spine to have some hardness for the sake of rigidity.

Or, you can just leave the whole blade hard and mount your handle.
Yea, mine was left hard just to see what it would act like. I dont remember what I did exactly, so I guess I need to do another one. I know it was hell on belts. I did a lot of the hogging with a bench grinder, but the final shaping with the belt sander was still very slow. I'm only using a 1x30 though.
Question, you state "carbon steels" will break into three pieces if you try to pry with them. Ontario Knives told me that 1095 was much better than D2 for prying,etc. I have read that steels like 1095, 0170-6c, 5160, 52100, A2, are fairly tough (though not as tough as S7, or 3v). Which carbon steels are you referring too? Can you be specific?
Ron Athay
I REALLY like my 4'' Anza EDC type knife. I've been using it for about 8 years or more and it's still going strong. Sharpens easily, holds a decent edge. Take care of it and it will take care of you.
Wow me2!
A 1x30 is a chore to use when the file is left fully hard. But, the end result is well worth it. Using a knife you made with your own two hands is an amazing feeling of accomplishment. I hope your next effort is easier(often the more knives you make, the easier it becomes).
This is why I like this place always someone willing to share their understanding, always learning something new here.
A lot of the rough grinding was done on a bench grinder. I must admit that I softened the next file before grinding. It was also much smaller. The first was made from an 8" file, about 1" wide. The next was made from a 6"x1/2" file. I havent hardened the second one yet. Hopefully this weekend I'll have time to make another kiridashi. I harden these harder than the file, somewhere near 66 HRc if past results still hold. I'm up to about 6 knives now, but each one has been different, so there's not that much repeat learning. Maybe I should stick to one pattern until I can do it efficiently. Thats why I like kiridashi. They are about as easy as it can be.
Yeah, I hear ya! Hoggin' on a bench grinder is the ticket. Sure saves money on belts.

My first attempts were straight-backs. Then drop-points as I got used to the actual process and then went on to clip-points. The part, for me, that required the most work to get right was matching up those plunge grinds on the ricasso. That took a LOT of practice for me. I hope you catch on to that much faster than I did.:)

Mastering one pattern at a time is a good game plan, but it's not a set-in-stone kind of thing. Each maker progress's at his/her own rate as their confidence builds.

Good luck with your upcoming projects.:thumbup:
The part, for me, that required the most work to get right was matching up those plunge grinds on the ricasso. That took a LOT of practice for me. I hope you catch on to that much faster than I did.:)

Thats what chisel grinds were made popular for. The hardest part so far has been getting the taper right and not taking off too much at once, so at the fine grits, I still have something left to polish. Keeping the grind lines straight is another tough one.
The Anza shop is about 15 miles or less from me. I should go check it out. I discovered the company at the local gun show some years ago and bought a couple of their knives when they said they were local. One of the best knife buys I've ever made. I believe I only paid about $10-$15 each for them. This was probably about 11 years ago. Great people. I saw them at the most recent gun show and found out that the "big" guy that I bought my Anza's from had an accident I believe. From what I was told, he was a big part of the company. Too bad.