knifemakers - I got this old file

[dlpowell]

Well, I have an old file. 3/16 thick, 2" wide. 12+" long. The teeth are dull and unusable. I want to make a knife out of it.

Do I just work it down on the belt sander or does the metal temper need to be changed?

 

[ameling]

First make sure of what you have INSIDE that file. Many files are made from soft low-carbon steel with the outside being case-hardened. And those junker files will not heat-treat.

Heat-treating a knife blade made from a good file is no easy thing to do. Professional knife makers have a hard time getting a good heat-treat on a file knife, and that's with good equipment.

Good luck on your project. But make sure of what you are starting with. The first time a friend spent 40 hours forging/grinding/filing/sanding on a file knife only to have it not heat-treat taught him that hard lesson. That is why so many professional knife makers start with new steel.

There are a lot of ... romantic images ... in making your own knife, and also making it out of an old file. Get past that quickly.

Mikey

 

[smokehouseman]

What's the procedure to find out what's on the "INSIDE"?

 

[BillinOregon]

If you start with a Nicholsen, and not some file made in China, you have a very good chance of having a decent piece of steel. First thing you want to do is anneal the file, which softens the steel from file-hard to workable. Do this by heating to a cherry red, or until a magnet will no longer stick to the steel. Then let it cool slowly, preferably in a tub of vermiculite. You should then have a file-shaped blank of dead-soft high carbon steel. Shape as you wish by forging and filing or stock-removal grinding, then heat again to non-magnetic, quench to re-harden and temper -- the tricky part. Mikey knows waaaaay more about this than I do.

 

[LRB]

Put the file in a vise with maybe 3/4" or so of the tip above the jaws. Wear eye protection, whack it hard with a hammer. If the tip breaks off chances are you have good steel. If it is a Nicholson you have good steel and don't need to do that. I have never had a problem heat treating Nicholson files, or Simmons for that matter. After you finish all the shaping, heat to a red even heat in dim light 3 times letting it cool to black, or even room temp in between heats. This is a stress remover. Then heat about two shades of red ABOVE non-magnetic and quench in canola, peanut, or mineral oil that has been heated to 130°. Immediately temper in your kitchen oven at 450°, use an oven themometer. Don't trust your range setting. Temper twice for 2 hours each, letting cool to room temp in between. To get a more even heat in the temper, bury the blade in dry sand. They make very good knives, especially Nicholsons.

 

[J.D.]

If you don't have access to a forge, just temper per Wick's instructions, then rough grind with coarse wheels. Move to finer wheels or belts for final grinding.

Grind with bare hands to prevent overheating the steel. Quenching in water will cool the blade, but be sure to dry it before you begin to grind again.

Wet, hot steel can cook your fingers if not careful.

While grinding hardened, and tempered steel is easier than grinding fully hardened steel, it isn't a walk in the park. Making a knife out of a tempered file is very time consuming, tedious work, but it can be done.

God bless

 

[LRB]

JD is correct. That is another way you could go. As he said, take your time, and never let it overheat. If you see color in the steel beyond a dark straw color, you have ruined the temper, or at least lessened it's hardness. Quality files have a wonderful grain size and structure as they are, so in many ways you could be better off going with JDs suggestion. Slow going, but you would end up with a great blade.

 

[dlpowell]

This file has no identifying marks on it. I've been dragging it around since the eary 70's. It was wore out back then. Wouldn't cut at all. So should be decent steel. I stuck it in a fire yesterday for about 4 hours. Was smoking a brisket, took one look at all those wood coals, and knew that file needed to go in there.

 

[NJStricker]

You should ask yourself why the file was worn out, especially if it has no identifying marks. It could be that it just wasn't a good file to begin with. . .

 

[crockett]

One other thing about making knives from files,after you grind off the file teeth the final knife is going to be a little thinner, and smaller than you may have first thought- so plan the knife that way. Some of the smaller knives carried in a neck sheath- that might be a good style to copy.

 

[DBox]

I like making knives out of GOOD files. That means one with a brand stamped on it and is made in the USA, England or Germany. I first anneal the file in my charcoal grill. I do this by laying out a layer of charcoal briquets, place the files, usually several, on this layer, place another layer of briquets over the files, sqirt lighter on the pile and set it on fire. This next step is VERY inportant. After the charcoal turns white, I put the grill on and cook a bunch of burgers, chicken, pork chops, steaks or whatever. Don't disturb the charcoal and leave the lid of the grill open. the next day take the files out and store them until you are ready to make a knife. The charcoal will heat the files and the ash will insulate them and let them cool slowly. You can bend them when you take them out.
When I shape them, I start on a bench grinder and get it shaped like I want it. Then I grind the teeth off of the blade section. I leave the teeth where the handle will be. There is no reason to spend the time grinding them off if they are covered up and it's kind of neat to be able to see them next to the handle if you use scales. Don't put the final edge on until after you finish the knife. Otherwise you may melt a chunk out of the thin edge when you harden it. Get the knife almost finished and all of the deep scrtches and grinding marks out of it, then harden it. I heat the entire blade; back, handle, blade, everything, to a red, non-magnetic heat and quench it in water. After it cools, I put it in the oven in the kitchen and temper it by bakeing it for about 1 1/2 hours at 400 degrees. Then I turn the oven off and leave it in the oven until it's cool. Then take it out, finish the edge, the handles, do the polishing and enjoy. If it doesn't temper right, I re-harden and re-temper it. This is not the only way and probably not be the best way, but it's the way I do it.

 

[J.D.]

IMHO, lump charcoal gets hotter than briquettes, so, IMHO, its more likely to get a good anneal with lump vs briquettes. I just hardened a pattern welded blade for my son that was heated in a forge using lump charcoal, 'cause its faster to get a usable fire than burning coal. IMHO, Larger lumps banked around the blade seem to heat the blade more evenly too.

That blade went to non-magnetic with very little blast from the blower. It didn't take much more to bring it up to hardening temp.

I also anneal small parts by placing them on a large lump of lump charcoal, covering with a coupla other large lumps, and allowing it to burn down to ash.

IMHO, file steel is usually W1, W2, or something near 1095, so it needs to be heated another 75-100, or so degrees above non-magnetic...a coupla brighter color ranges above the color of non-magnetic, to get the best out of it.

IMHO, testing the newly hardened blade with a dull file will tell you if it's hard enough. If not, throw it back into the fire for another try.

IMHO, testing a blade for hardness right out of the quench will save having to repeat the whole process, if the blade comes out too soft.

IMHO, it's is not recommended to quench thin cross sections of file steel in water. Warping and cracking are likely to ruin all of your hard work.

IMHO, if you want the best out of a knife made of a file, follow Wick' instructions. He knows what he is about.

God bless

 

[rich pierce]

All good advice. And I'll add that you don't want to get caught up making it harder than it needs to be. You really don't want your knife to chip or snap someday. It's not that hard to touch up an edge, but a snapped tip will make a grown man bawl.

 

[LRB]

I think JD had the best suggestion. Grind it as is, keeping it cool. The main concern with heat treating is the quench, and pre heats. This sets the steel up for the final out come. If not done right, the out come will be less than it could. That file has already been through the most critical steps in heat treating, and it is unlikely that you would ever match its present internal condition, except you will soften it a little to take out the brittleness. You might do well to temper it before you grind. That would remove the risk of it breaking if you dropped it, and make it a tad bit easier to work on, and reduce any stresses or warping that would occur while you work on it.

 

[ladysmithtrading]

A question here for Wick and all, I read a year or so ago in a publication or a bladesmith sight (can't remember which, growing old and forgetful, what was I talking about? oh yea!) when quenching the steel, orient the blade to magnetic north/south line with the blade side north, supposedly helps the molecules with correct alignment, any thoughts on this boys?

 

[paulvallandigham]

Japanese sword makers are reputed to have aligned their stone quenching tanks with the magnetic North, to improve the quality of the steel as you describe.

It can't Hurt, but I have never heard or read any modern source indicate it makes any real difference. According to modern science, the Magnetic North Pole is moving every year. Its now under the Polar ICE CAP, where it was, when I was a kid long ago, at the upper end of Baffin Island.

 

[DBox]

If you take a file and hit it on and anvil, table edge or concrete, it will brek because it is brittle. If you grind a file and don't heat treat it, your knife will have the same properties and will break some day. It's not hard to anneal it, heat it back to red (BTW, I use a coal forge for this step, not charcoal), stick it in a bucket of water, take it out, put it in the kitchen oven for a while, and polish it out. It also saves a lot of wear and tear on grinders and belts if you anneal any steel.

 

[Adam Isrow]

All this talk of knifemaking is getting me motivated. I have a couple of old files. Think I'll throw them in the campfire this weekend. :grin:

 

[dlpowell]

Alright guys. Lastnight I grabbed the file from the charcoal grill,went to the shop,stuck it in a vise,and took the cut-off wheel and grinder to it.

Man was I surprised at how soft that steel was. Cut like butter, ground easy, and in about an hour I have the knife roughed out ready for file work.

Have a small strip of metal for the guard also.

I'll smooth it down by hand. Stick it in a hotter fire then drench in oil.

Thinking about wrapping it in an oven cleaner soaked rag to age it.

 

[LRB]

According to the metallurgists, no, and I believe them after trying it myself. Most often makers do this thinking it prevents warping. It sadly does not. If only it were that simple. I quench point down as that is the part of the blade that will lose heat first, out of the fire or oven. Non-magnetic begins at 1414°. It does not return until the steel cools way down. At least below 800°, or 900°, maybe even lower. I don't remember at the moment. This is atomic science at this point. There are no molecules in steel, other than the carbon, or other additives, which make up a small percentage of the steel. Steel is a crystal structure, with groups of atoms making crystals, groups of crystals making grain units. Carbon and iron atoms are in cubicals. Enough heat will make the atoms change position in these cubicals, which makes the steel non-magnetic while the atoms are in motion. The degree of magnetism returning, will relate to the degree of motion in these atoms as the steel cools. I can tell you that after a blade cools to around 400°, there are still atoms in motion, because using gloved hands, you have about 5 minutes that you can straighten warpage. After that, it may break. It will not be full hard for a few more minutes. I would agree however with Paul. It can do no harm, and if you could prove that it does in fact work that way, you could embarass a lot of metallurgists. Many years back I tried quenching edge down pointed north, point down with the spine north, then with the edge north. I always got the same results as I get today. Some warp, some do not, no matter the direction.