Knife making from a file

[Tommyd345]

Hi all,

Iv been looking at making a knife from a file (because it looks easy-ish) I was wondering if there's a particular file that is good? What sort of things should i be looking at? Also do I need to heat treat it?? Also are there any good files I would need for grinding the bevel?

If this needs to be moved then please move it

Thanks
Tom

 

[David LaFerney]

A good file such as a Nicholson are made of appropriate steel and are tempered to a very high hardness. If you can do what shaping you need without getting it too hot all you need to do is temper it in a 425 (more or less) degree F oven for about an hour - cool - repeat. That will reduce the brittleness enough to make it a usable blade.

However it will be very hard to work and almost impossible to drill.

I've done this and the result can be a knife with very good steel qualities - hair poppin' sharp, and good edge holding but easily re-sharpenable. The factory has already done the difficult part of the HT - hardening - for you.

Because the metal is hard to work you want to keep the shape simple. If you do the grinding bare handed you won't overheat it except (if you aren't careful) on the sharp edges because it will get too hot to hold before you draw the temper too much.

Otherwise you would anneal it by heating it past critical temp and cooling very slow to make it soft enough to work then re-heat treat after. Much more technical, but completely doable - even using just a grill.

Either way - making a file knife is a good way to start.


Good luck.

 

[pieinthesky]

Farriers Rasps are good for a large knife and are not too thick. They are generally about 5 x 45 x 350 They make a good camp knife.

They are variable in quality from make to make. I have found Save Edge and Bassoli to be OK. If you know someone who has horses they will likely find you a few if they ask their farrier.

Tempering and grinding hard is a simple way to do it if you have the tools to grind without making it too hot. Drilling the handle for pins is difficult but if you use 3mm handle pins you can buy some 3mm carbide drills to make the holes. (Carbide drills are easily broken and the larger ones are expensive, so best to avoid large pins). Be careful when drilling as any irregularity left from the file teeth will deflect your drill and snap it. Grind a flat spot where you want to drill if you can.

If you are going to soften your steel and re-harden it might be a bit hit and miss as you probably won't know the steel type and might struggle to get it hard again. Check you can heat treat the steel before putting too much work into a piece.

 

[petrochemicals]

I don't think you are going to file the file with another file, as it may get wery expensive in files. If you really want a knife from a file, temper it first then grind it on a wet grinder of some sort. Do it slowly and make sure the work stays cool, so don't go too hard on it. As for shaping the handle, grind it before you grind the blade, you can dry grind it within reason as long as you keep it cool, but take it easy and don't rush it, especially as you approach the blade. I believe but an not certain that the cutting edge will have to be a resonably broad angle, so I wouldn't put a scandi grind on it. Finish flattening the blade by hand on a stone. Farriers rasps, if like wood rasps I think are different composition, far far less hard due to the differences in required tooth shap, you'll probably be able to file them, but wet grinders are far better andquicker. As for the heat treating I can't help you as I do not know the temperatures. If you get a piece of hardened steel that has specific heat treatment info it may be a better option.

 

[kristophish]

I use files for knives a lot. Look out for nicholson as said earlier but oberg file are great too. You cant use any file, old is better as newer cheap files tend to just be case hardened

 

[David LaFerney]

It just occurred to me that you can soften the tang enough to make drilling much easier - just wrap the blade end tightly with a wet cloth then heat the tang red hot with a torch and let it air cool - normalize. It won't be butter soft, but it will be way easier to drill.