View Full Version : What files are best for blades
17-05-04, 08:32 AM
After seeing some fine knives made from rasps and files and having traweled the car boots this weekend and seen loads of old used ones. What should I be looking for in an old file to make a blade. Should I be thinking stock reduction? forging? and what HT process am I going to need?
17-05-04, 09:32 AM
As you're probably aware, a number of file manufacturers like to use case hardening for their files; the older the file, the more likely it is to be high carbon.
Either way, you're probably going to need to anneal it before working it, unless you are grinding it but keeping it cool; grind the teeth off for preference (stress risers) - unless you intend to keep them as a feature. Nothing fancy, just an angle grinder - I don't use my expensive belts for this stuff unless I have to!
Proviso after proviso - sorry. :D
HT - depending on size - can be done with a 1 brick forge & a propane torch.
17-05-04, 11:59 AM
What is the one brick forge?
17-05-04, 12:13 PM
A single soft firebrick with a 1" ish hole down its length, and another one in the side intersecting.
Stock goes in lengthways, torch goes in sideways.
I have made quite a few knives from old files leaving the file cuts on, stock removal and forging.
Its pretty common.... many knife makers experiment one time or another with old files
There is at least one knife manufacturing company that makes all its knives from old files...called ANZO...Here is a link of some of their knives from the Knife Outlet site.
Knife Outlet http://www.knifeoutlet.com/shop/10Browse.asp?Category=Anza%20Knives&src=OVT
Its possible to immediately temper the file from its original hardness, to a working knife hardness.......(as a guess, maybe a couple of hours in an oven at 400F+- to draw some temper ?)....You could then grind it to shape if you were very careful not to overheat the steel...keep dunking it in a bucket of water.
A knife from the original file hardness is IMO too hard...I tried it, and it chipped too easily.
Its probably more common to anneal the file to soft, grind then re harden...Or, forge it then re harden.
If you check the ANZO knives you will notice that they dont use pins or bolts to attach the slab handles......just epoxy. I tried this a couple of times, utilizing the course file and roughing the inside of the handle material to get a good bond which worked well (handles are still on 2 years later).
If you are unsure if the file is case hardened or not, then cut or snap the end off , anneal, then re harden and see if it hardens. If its case hardened it will not. I once spent a long time forging a large dagger from a rasp file, to subsequently find that I couldnt harden it.
(any scrap steel you use for a knife, its always recommended to harden a piece before you start!)
I would always quench a file in oil and not water as the file cuts may cause stress risers, and water would be more likely to crack....I have not had any crack in oil.
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