View Full Version : Quenching files

09-11-2004, 10:40 AM
I've seen 2 different opinions on quenching knives made from old files. One says oil, the other says brine. Both say not to use the other. Anybody made a knife from an old file? Which quench worked? :confused:

Also, one reference insinuated that file metals have changed over the years. Would that be the reason for 2 different quenches?

From time to time, I pick up a broken file at work or a few old ones cheap at a garage sale. No use in making a knife if I'm not going to get a good quench.

Alan L
09-11-2004, 10:47 AM
I've made a couple, both from old Nicholson files. Oil quenched both of them, and they seemed to do just fine. I treated them as if they were W-1, but the smaller one acted like 1095. Keep in mind I'm not an expert, though. :)

09-11-2004, 03:22 PM
Jusr finished one from an old unmarked file. I quench tested the end before I started and when I finished I quenched in veggy oil in a cake pan right beside my forge. I have had too many crack in brine, I probably dont mix it right. "I can hold it there just a little longer........PING...... ^&%*$ " and yes that is a direct quote.

09-12-2004, 12:25 AM
Oh, deja vu! I've heard that same quote in my shop! Sometimes on the grinding belt, sometimes on the buffer, .......

Ed Caffrey
09-13-2004, 09:03 AM
If you stick with Nicholson files you should be in pretty good shape by using pre-heated, light viscoity oil. To my knowledge, Nicholson is the only company left that uses high carbon/alloy steel to produce their files. Eveyone else has gone with case hardening. A few years ago I had several files spectrographed.......... The regular Nicholson files came back as 1095, and the Nicholson "Black Diamond" files came back as a plain carbon steel with 1.27% carbon. The rest (Fisher, craftsman, etc) all came back as case hardened steels of various make up.

So, it can be a real crap shoot if you just grab any old file and go for it.......

09-13-2004, 09:35 AM
Does anyone have info on PlastiCut files? My neighbor has access to barrels of them. I did take one and heat it up and quench in water. It shattered into several pieces when I smacked it with a hammer. It also sparks pretty well on the grinder, but I have no clue what steel it is.


paul harm
09-13-2004, 02:51 PM
sounds like you have a good steel for knives . why don't you make up a small one and see if it will pass the brass rod test ? knives from files with a thin cross section gives a good edge geometry and they seem to hold an edge forever . it would be nice for you to have a supply of good steel . paul

Chuck Burrows
09-14-2004, 10:22 PM
FYI - Case Hardened files are nothing new....
"Take ox hooves, and put them into an oven to dry, that they might be powdered fine; mingle well one part of this with as much common salt, beaten glass and chimney soot, and beat together and lay them up for your use in a wooden vessel hanging in the smoke; for the salt will melt with any moisture of the place or air. The powder being prepared, make your iron into a file, then cut it chequerewise and crossways with a sharp edge tool. Having made the iron tender and soft, then make an iron chest fit to lay up your files in and put them into it strewing on the powder of course, that they may be covered all over; then put on the cover and lute well the chinks with clay and straw that the smoke of the powder may not breathe out; and then lay a heap of burning coals all over it that it might be red hot about an hour; when you think the powder to be burnt and consumed, take the chest out from the coals with iron pinchers and plunge the files into very cold water and so they become extremely hard. This is the usual temper for files; "for we fear not if the files should be wrested by cold waters."
This is from the 13th Book of Natural Magick, 1589, GB Della Porta

09-16-2004, 09:26 PM
Heat 'm, beat 'm, quench 'm, test 'm. Some of the imports will surprise you. They are not all case hardened, just most of them. It's so easy to find out.
I've gotten my best results with the Black D's using 120 to 130 deg. olive oil (double virgin of course!).
Most of them forge like butter compared to other steels and the price is right. They also make excellent wood chisels and turning tools.

Fox Creek
09-19-2004, 10:42 PM
I have forged blades out of files marked "Nicholson", Black Diamond", India", and "China," and who knows what else, maybe ACME Supply Co. :p I have never a failure to harden nicely in thin, hot oil. And they do forge like BUTTAH! I think that the "case hardened' theory is OK, but unlike Medieval anecdotes, the case hardened files we have today are maybe 1070 steel, case hardened on the teeth to maybe 1095 level of carbon. So, the whole thing aint bad. Thats all I can think of to explain my experience. :cool:

09-21-2004, 08:52 AM
Well I finally got around to using one of thoes Plasti-Cut files. I just ground it into shape since it's pretty thin to forge. Anyway, heated it to non-magnetic, quenched it in heated ATF and tempered it twice (once for an hour at 400 and then for an hour at 375). The knife takes an edge pretty good, cuts well, and passed the brass rod test. I did etch it in ferric chloride for about 15 minutes and did not see a hamon line at all. The file mush be some kind of alloy. I guess time will tell wether or not these files will make decent blades.


paul harm
09-21-2004, 10:01 AM
jason , did you edge quench the blade ? if you quenched the whole blade you won't see a line . try putting about a 1/3 of the blade in for about 3 seconds , out for 3 , and back in a bit deeper - hold till all the color is gone from the back of the blade , then put the whole blade in . a lot of times you get a double hardening line . paul

09-21-2004, 02:08 PM
Yes I edge quenched it as per your description above, but nothing. I have a bunch more files to mess with, so maybe I will get different results as I figure out the process.


paul harm
09-22-2004, 08:46 AM
what are you using to etch the blade in after h.t. ing ? i've always had good luck with ferric cloride . maybe you're using too mild of an acid . just an idea - paul

09-22-2004, 09:20 AM
I am using ferric chloride "solution" from Radio Shack. The directions on the bottle say to use it straight, do not dilute. I suppose it could be too weak for what we are doing.

I ground and H.T.'ed another blade last night and after cleanup and etching, I did get a faint line in this one. However it was so faint, 600grit paper polished it out.

paul harm
09-23-2004, 03:06 PM
just about everyone uses 1 part f.c. to 3 or 4 parts water - you may have to do it more than once . i usually dip , then sand with 600 , and repeat 3 or 4 times . try dipping again a couple of times and see if it helps - paul

09-23-2004, 03:22 PM
It's hard to bring out a hamon sometimes, you'll need to do multiple etches with cleaning in between. When I etched some damascus I was amazed at how easy it was compared to trying to do a hamon, one dip and it looked like damascus. You'll want to etch, sand lightly, and etch again until the hamon shows after the sanding, though I'd use a higher grit then 600, I'd use 1000+ grit.

09-23-2004, 07:57 PM
What Paul said. Straight from the bottle is to strong etches everything fast. Dilute and run through the procedure several times for better results. Directions on the bottle are for etching electronic circut boards - dissolving copper film at a fast rate. Take your time and be patient.

Chuck Burrows
09-26-2004, 01:04 PM
I think that the "case hardened' theory is OK, but unlike Medieval anecdotes

Richard if you read that closely he's basically making "blister" steel which was the "basic" method of the period - blister steel essentially being a deeply case hardened steel.

09-27-2004, 09:04 PM
OK, I must say thank you to all the good folks who have posted here, I just finished my 1st forged blade (after three failed attempts, may not be too bright but I'm stubborn). And I tried to quench in brine (mistake), she cracked but good on me.
So I ground down the flaws put her back in the forge (a period WWII Military coal forge) and redid the blade. On the advice of a Metalurgist engineer friend of mine I quenched it in Straight Anti-freeze diluted 10%, and darn if it doesn't work great.
I'm using the leaf springs out of an old car, lotsa fun heat em up cut on the anvil then 'rip' the cut piece on the anvil again. Never dreamed this could be so much fun. Lookin forward to #5 blade tommorow night.

Any comments would be welcome . . . .

Sean McCulloch

Fox Creek
09-27-2004, 09:29 PM
Richard if you read that closely he's basically making "blister" steel which was the "basic" method of the period - blister steel essentially being a deeply case hardened steel.

Well, of course chuck! I guess there is a difference between making blister steel and just case hardening a poor edge on WI, but it would be just in degree, or would that be a rhetorical distinction. ;)
and SEAN, I have never heard of hardening in an antifreeze solution. THAT is a truely new one here I think. I hope folks try it and report back. makes sense intuitively.