DMT’s W4F Diamond Pocket Whetstone has the fine grit matrix you most often need when touching up a blade edge at work or far from home. This 4 by 7/8 by 3/16-inch sharpening stone weighs only a little more than three ounces, including the neat stitched leather sheath. Ultralight travelers could save a little more weight by leaving the sheath at home. Just be careful the whetstone doesn’t wear a hole in your pocket.
When new, the surface of the steel matrix (which actually carries the fine diamond grit) will cut faster and rougher than expected. As the surface wears, the stone produces slower results but a more finished edge. After that first rough layer wears away, the stone stays virtually unchanged for years. Natural or ceramic stones quickly develop dips — not so much a problem with knife blades as with chisels or planes, which must stay perfectly square. Diamond stones continue to give accurate results for years of heavy use.
The fast cutting action and light weight of this small but efficient honing stone make it a great choice for campers, hunters, fishermen, and hikers. You can even skip the honing oil since the diamond stone works either wet or dry. To prevent buildup of metal particles on the surface, moisture the stone with a few drops of water before use and rinse it clean when you’re done. While this grade of stone won’t create a mirror polish on a blade, the edge it leaves is good enough.