www.ragweedforge.com Ragnar has both diamond plates and a traditional viking stone in small sizes. The stones, besides beautifull ( who says survival has to be grim black epoxy or international orange <img src="/images/graemlins/grin.gif" alt="" />) do a very good job within their limits. The smalll two sided diamond plate lends itself to many ways of attachment. On my old Cold Steel SRK I slipped it underneath the paracord wrapped around the sheath. You might also consider a few sheets of wet/dry sandpaper in your PSK. Lee Valley tools sells superb sheets used for wood chisels.