How to Sharpen a Seat Belt Cutter on a Knife

How to Sharpen a Seat Belt Cutter on a Knife
Clockwise from top: Emerson Knives NSAR, Benchmade 10 Hook, Hogue HK Karma and the Ontario Model 2. All sport seat belt cutters (aka strap cutters). (Dexter Ewing photo)

A question often asked is, “How in the world do I sharpen seat belt cutters?” It’s not really as difficult as you might think. All you need is the correct sharpener.

The Best Sharpener for Seat Belt Cutters

The DMT FSKC serrated sharpener is a great choice for tuning up seat belt cutters. (DMT image)

Because you’re sharpening a cutting tool that has limited access to the actual cutting edge, I recommend something like the DMT FSKC serrated sharpener. It is a coarse-grit, diamond-coated, tapered rod commonly known as a rattail file.

Sharpening Seat Belt Cutters

Working the cutting edge from the ground side only, carefully work the file with light pressure, ensuring you run it over all of the exposed cutting edge.

On the reverse side of the blade, which is flat, feel very carefully for the burr that will form. Once you feel the burr, you know you have done it right. On the flat side, take the rattail file and, holding it as flat to the blade as you can, lightly “wipe off ” the burr. You might have to return to the ground side to wipe it back to the flat side.

Stropping Seat Belt Cutters

Another thing that helps is stropping the inside of the hook with a leather shoelace. Have someone hold the unsheathed/opened blade by the handle for you, then firmly grasp both ends of the shoelace and lightly “floss” the inside of the cutting hook. Move the leather string only in one direction—down the cutting edge. If you move into the edge, it will cut the shoelace in two.

Repeat the correct motion a few times to strop the ground side. It is basically the same principle as stropping a straight razor.

Sharpening Tips

Provided you don’t use the cutting hook for anything outrageous, such as cardboard, and you use it sparingly, you won’t need to sharpen or strop often. However, in the event you do need to restore the edge, this is how it’s done.

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