A dull knife is just plain dangerous, so it's been one of my lifelong missions to find the perfect knife sharpener.

And last week I found it in the Work Sharp knife and tool sharpener, which comes with a promise to produce razor edges.

A few passes of my pocketknife proved the sharpener lives up to the hype. Watch the video to see how easy it is to achieve edges sharp enough to shave. I even used the sharpener to rework the edge of a machete.

The Work Sharp sharpener uses belts that come in different grits to provide flexibility. The belts are easily changed so you can move from the coarse- to the fine-grit belts.

The real trick to the Work Sharp sharpener is that there are guides that automatically set the angle of the blade to produce the perfect edge. Just pull a knife across the belts, with the blade pressed onto the guide. It's that easy.

The original Work Sharp comes with two guides: one for outdoors knives (pocketknives, fillet knives and the like) and sissors, and one for kitchen knives. Just switch the guide to automatically get the perfectly angled edge.

And the guides can be removed to allow the sharpener to be used on other tools like shovels and mower blades. You can even rotate the head so the belts can be worked at different angles.

The company also offers manual sharpeners for those times when electricity isn't available.

The original Work Sharp knife and tool sharpener is very inexpensive, costing only $89.95 — and it's worth every dime. A new Ken Onion edition targeted at high-end kitchen utensils costs $168.