knife making

[monkey boy]

i want to make a knife out of a file, what should i be looking for in the file i use?
the reason i want to use a file is because iv designed a knife that needs the teath,

also is there a way i can do the whole job by hand without any electical tools?

many thanks monkey boy

 

[JohnC]

I made one using an old file from a junkyard. I believe older files have a "better" steel for hand working. I put it in a charcoal fire while working on other blades and left it overnight to cool as the fire died away. This removed the brittleness of the file and allowed me to cut it with a hacksaw and use handfiles on it.. I found it a good way to get a nice bit of steel for a blade. I found no problem with hand tools.

 

[shep]

Have a look here for a good tutorial.

 

[Peter_t]

the reason i want to use a file is because iv designed a knife that needs the teath/QUOTE]

so you still want to be able to use the file afterwards? if so you have a problem. files are tempered very hard, this makes them brittle so the knife could snap under use, easy get chips in the edge and be inposable to sharpen OR you could temper it softer (ordanary knife hardness) and have a good stong knife which you can sharpen but the file teath will be too soft to cut with.
so realy yo can only have one or the other.

always go for old files, much better quality steel than those made today but it will almost definately be blunt.
hope this helps

pete

 

[Dave Budd]

not quite true about old files being better, only a generalisation some old files are rubbish and some new ones are great. if you buy a cheap file you get monkey metal, if you buy good quality files you get good quality steel

Best way to find out what you have is to place it in a vice with an inch poking out and smack it with a hammer. If it snaps off cleanly then it's a good one, if it bends then it is not!


As for making one into a knife. easiest way is to anneal it and then grind/file/saw/forge into shape before re hardening and tempering. You could grind it into a knife and re temper to a softer more suitable hardness, but you would have to grind it without heating it above 200C and that is a very slow process!

 

[Peter_t]

not quite true about old files being better, only a generalisation some old files are rubbish and some new ones are great. if you buy a cheap file you get monkey metal, if you buy good quality files you get good quality steel

yes but old good files are cheep
what good file makes are there? iv heard sandvik/bahco are good and valorbe (spelling?)

pete

 

[monkey boy]

where can i get the old file from, as im not looking to spend much money

 

[brancho]

You can get old tools at car boot sales market stalls and some auctions as job lots.

I would think old wood chisels would be usable as knofe making material in the way Dave suggest as well.

 

[Matt.S]

Case-hardening files is as old as the hills; Theophilus (12th Century) wrote about it and I suspect if the Mastermyr Find files and rasps (badly categorised) were probably case-hardened though I don't know if they've been analysed for it. The age of a file, as already mentioned, does not in any way indicate whether it's case-hardened or homogeneous steel.

'Black Diamond' brand files are apparently very high carbon (c.1.2%w), probably too high for a general-purpose knife. I'd say that anything marked 'Sheffield' will be a decent high-carbon steel rather than case-hardened mild steel or zero-carbon iron (or 'monkey-metal' as Dave so puts it so well ).

If your design incorporates file 'teeth' you can carefully add them to a plain piece of steel, whether with a cold chisel and hammer or a file.

 

[monkey boy]

thanx guys thats very helpful, just to let you know, the design i have in mind isnt to be able to use the knife as a file aswell, i need the teath on there for patton resons, il show u all pics when i get a file to do the job
monkey boy

 

[Dave Budd]

most old tools (or new ones for that matter) can be good or bad steel, so all you can do is to try a bit and see. Cut a piece off and try hardening it, then temper at different (increasing) temperatures until you get the hardness that you desire.

Old chisels, drawknives, plane irons, etc are often good stuff, but beware the cast steel ones, they often shatter if reforged! That said, I've made all sorts into knives in the past, including HSS twist bits!

MattS, 1.2% isn't too much for a general purpose knife, if it were then I would've been having real trouble with my blades over the last few years I wouldn't use it for large blades like parangs or billhooks though. Tempering a hgh carbon steel will still produce a spring, but it will work harden and fatigue more quickly than a medium carbon steel will do

 

[Matt.S]

MattS, 1.2% isn't too much for a general purpose knife, if it were then I would've been having real trouble with my blades over the last few years I wouldn't use it for large blades like parangs or billhooks though. Tempering a hgh carbon steel will still produce a spring, but it will work harden and fatigue more quickly than a medium carbon steel will do

Good point there Dave, there are numerous documented spring-tempered long blades (swords) up to 2.2% carbon (the limit of what is generally considered to be steel). Tempering 'at home' by a novice becomes more difficult though; with 1% carbon steel you can temper down to the low 60s Rockwell C (probably the upper limit of what you want for a homogeneous general-purpose knife) in a kitchen oven (220-odd degrees C), which is a bunch easier and more predictable than using a fire for a novice.

Out of interest are you warning against the forging of directly-cast steel tools or tools forged from 'cast' (Huntsman crucible) steel or both?

 

[Dave Budd]

hard to say. on occasions I've reforged tools labeled as 'cast steel' and they have fallen apart. I suspect that it was just beause I had them too hot when working on them. Any steel can be reworked once you know how to work with it but you need to try a few bits and experiment to find out how, which is not always possible if you have a single chisel to convert into a blade.

Forging unknown steel is always interesting as every steel has a preferred working temperature besides the heat treating temps. For example I was playing with some D2 the other week. Too hot it's cheese (high carbon but also high chromium content), too cold it snaps (air hardening steel); so the right temperature has to be maintained and in this case the ideal forging range is very narrow:about 90C!

 

[bivvyman]

Be careful, you may get several hours work into making the knife of your dreams only to find its no suitable. The high carbon content of all half descent files is high, if it is not tempered correctly, although been rock hard , will be very brittle!

So, once you have made your shape & thinned the blade edge, polish the steel quite bright, heat the whole blade only to a red hot heat, (not the tang) quench in old oil, then polish bright again, heat the whole back edge of the blade 1st , you will see a rainbow of colour appear from red heat to yellow on the blade tip. when the heat colour is light purple on the whole of the blade edge, quench in water. The tang should not be touched with direct heat, as this will be quite maluble . good luck.

The test drop it on a stone flag , flat. If it shatters , start again. they are difficult sometimes to get just right, why not buy a raw blade £3 - 7 !

 

[Dave Budd]

Save yourself even more work by taking said file and clamping it in a vice with an inch sticking out. Smack it with a hammer and if it snaps cleanly then you have a good one. If it bends then it ain't

or just chop a bit off and test heat treating, but don't wait until you are nearly done or you might kick yourself as mentioned