Chisel Bit Flat File, 7" - PFERD Brand

Very fast delivery, haven't tried it yet, but PFERD is good quality

Definitely the file to use for hand filing your square ground chains. The file's bevel edge sharpens the same amount of side plate as the original factory grind, unlike other file brands whose bevel edges only sharpen a fraction of the side plate that the original grind sharpened. Also, with four sharpening pairs per file, flat edge - bevel edge pairs, one gets one more sharpening pair per file compared with the triangular six-sided chisel bit files. These file's are great.

I have been using them for several years now and I love the aggressive cut I get when I sharpen with a flat file.