Files for Knives

[Old Hippie]

Just curious, because I've some badly worn files around that are looking to be repurposed. I seem to remember a discussion somewhere that modern files are hardened by a magnetic induction process (case hardened) using steel that doesn't harden well by more conventional heat and quench methods. As I recall, it was to the effect that any file made in the last 20 years or so was only good for the landfill.

Can someone clarify that for me? While there seems no shortage of old files in garage sales and junk shops, I'd like to recycle a few of my newer ones if possible. I've made file knives in past years with great success, but that was 30 years ago.

:ootd:

[Legba]

Heat em up, let em cool slowly. Craft then reheat to straw and quench.
They will be great for about anything you want. I get a lot of old files for 10 cents to a buck at the local garage sales and antique type stores.
Now hopefully someone will respond with a more scientific and precise answer for ya.

[Drac]

Most really old one, some older ones and a few of modern ones (mostly Nicholson) can be made into knives. The problem you run into is not knowing what the steel is. Both O1 and 5620 were very common steels used in days gone by but they heat treat differently.

One the knife forums I hang around on this question (and ones about bearings, saw blades, planer blades and car springs) comes up several times a year. The two most common answers are as follows -

1) Trial and error - Give it a try. Most carbon steels have similar annealing processes. I would use O1 as a default guild unless you know the make-up of the steel. For hardening normal is to heat to nonmagnetic and quench in oil. Than temper at 450f in you oven. Check out for list of temps http://www.knives.com/heatreat.html

2) Best recommendation is that since steels such as O1 and others are cheap it is in your best interest to just buy the steel (already annealed) directly. That way you know what the best heat treat for the steel.

Jim