Increment Borer Sharpening Jig

This jig is designed to align a sharpening stone with the cutting surface of an increment borer used in forestry for the collection of tree cores. The stone is scrubbed against the outer surface of the jig arm while the borer is rotated in the interchangeable holders. I haven't found excessive wear of the guide or plastic filling the stone to be a problem yet, but I want to improve this arrangement. Holding the stone against the inner side makes the the correct angle difficult to achieve and the borer difficult to rotate. Holders for two sizes of borer and a blank for making your own through mesh editing are provided. The clamp openings are designed slightly undersized; file the openings to the desired level of retention.

Planned improvements:
- clamping stop collar to hold the borer at constant depth
- improved sliding surface design for stone

I have an alternate version that works with Lansky-style stones and guide rods, available for upload upon request.