What To Look For When Buying Old Files

Thank you to Darrell, who emailed me with this request:
Do you think you could put together an article about what to look for when buying old files?

These cost $1 or $2 each. From top, mixed taper saw files, 12" Nicholson aluminum file, 8" Simonds, 8" Nicholson (mild wear), 12" Vixen  

This article describes how to choose old files at flea markets, yard sales, junk shops, or other places where used tools are sold. Please keep in mind that I am not a machinist, welder, or expert metalworker, and am relying on my self-taught experience and what I have read. For help identifying files, see this article by Paul Budzik.

Check for the brand or manufacturer’s stamp next to the tang. Avoid Asian files, which are inconsistent quality. Common Asian brands are JK and Sunflower. Others may just be labeled China or India. Some files are made in Mexico or South America, but I have no experience with those.

Check for signs of use or abuse. Shiny teeth will show where the file has been used. Taper saw files are a special case. They appear to have 3 sides but actually have 6 sides, with a very narrow row of teeth on each edge. These edge teeth are much more important than the flat sides. A taper saw file with wear on the flats may still be usable for filing saws.

Rust is the enemy of files, but you want to distinguish between surface rust and pitting rust. Surface rust, meaning light rust, can be removed by brushing, leaving the file usable again. Pitting rust will destroy the teeth, leaving the remaining teeth vulnerable to being sheared off in use.

Dirt and pinnings, meaning metal embedded in the teeth, can be removed by brushing or a sharp pointed object. Aluminum is especially difficult to remove. I use a small snap-blade knife, running it in between the teeth. A file is cleaned by brushing parallel to the teeth, preferably with a file card.

A bent tang is easily straightened in a vise, with pliers, or light hammering. The tang is not hardened.

Summary of acceptable files for use: made in USA, dirty, surface rust, light wear, bent tang.

Summary of unacceptable files for use: made in Asia, pitted rust, heavy wear (shiny or broken teeth), broken tang