Q. How do I know which size file I need for my chain?
A. A chain's original packaging should list the specific size file required for its sharpening. However, if you do not have the original package, you can usually determine which file you need by locating the pitch of the chain, which is often stamped on the chain's side. While not universally true, typically pitches of 1/4" or 3/8" Low Profile use a 5/32" diameter file, a pitch of .325" uses a 3/16" diameter file and pitches of 3/8" or .404" use a 7/32" diameter file.