File question

tbow

tbow

Joined
Nov 29, 2012
Messages
554
I bought several old files at a trade days show to make knives. I have annealed them and was cutting one to shape. I noticed when a piece was thin and I broke it off with a vice grip that it has a kind of porous look to the small part that broke. What does this tell me? Is this file case hardened only and therefore not suitable? Is this normal? This is not the first file knife I have made. The other time I just cut off parts and made a full tang. This time I am trying a less than full tang and using a solid handle. Any input would be greatly appreciated.
 
I have a paint can gas forge. Heated until non-magnetic. air cooled.
 
You have to go a lot beyond non-magnetic ... and hold it there for a good while to get large grain growth. What you see is probably just the way the file steel is grain-wise.

What you should do with any steel that is of unknown internal structure is thermal cycle it first to refine the grain, spheroidize the carbides, and leave it in the best condition for shaping and the final hardening.

This will require the following steps. Your paint can forge probably can't do this, BTW:

Heat to 1650F and hold for five minutes minutes.
Quench in fast oil.
Heat to 1350F and hold for five minutes.
Quench in fast oil.
Heat to 1250F and hold for 15 minutes ( do not go above 1275F).
Take out and air cool to 900F and then quench to cool to room temp. The quench here can be water or oil, it does not matter which, since it is only cooling down the blade.

Realize that all this may be totally useless since you have no idea what the steel type is.
 
bladsmth said:
You have to go a lot beyond non-magnetic ... and hold it there for a good while to get large grain growth. What you see is probably just the way the file steel is grain-wise.

What you should do with any steel that is of unknown internal structure is thermal cycle it first to refine the grain, spheroidize the carbides, and leave it in the best condition for shaping and the final hardening.

This will require the following steps. Your paint can forge probably can't do this, BTW:

Heat to 1650F and hold for five minutes minutes.
Quench in fast oil.
Heat to 1350F and hold for five minutes.
Quench in fast oil.
Heat to 1250F and hold for 15 minutes ( do not go above 1275F).
Take out and air cool to 900F and then quench to cool to room temp. The quench here can be water or oil, it does not matter which, since it is only cooling down the blade.

Realize that all this may be totally useless since you have no idea what the steel type is.
Click to expand...

Maybe I will re-anneal them and for a longer time. I don't think it will hurt. Since I don't have temp. control it's probably a shot in the dark anyway. No matter what I will try them out and worst case I get the experience gained and they didn't cost but a few bucks. Thanks for the input Stacy always appreciate your answers.
 
FWIW, I called Nicholson a few years back, and spoke to one of the engineers responsible for steel quality (didn't get his name or technical title), to try to understand what type of steel they used. Though the steel has a proprietary chemistry, he stated that it is very similar to W1 when it comes to heat treatment, performance, etc.
 
You must log in or register to reply here.
Back
Top