1.   A knife file is a type of triangular file that looks a lot like a flat file.

2.   He used no more than a rasp, triangular file and sandpaper, never measuring, never drawing plans.

3.   Small triangular files are also used to sharpen hand saws.

4.   Starting with the first tooth leaning toward you, make two or three passes with the triangular file.

5.   Triangular files have three tapering sides.

6.   Use a triangular file to mark the cutting line on the stock.