Drill Bit Re-Grinding
With the chuck set in place in to the jig-assembly, its as simple as turning on the grinder and adjusting the amount of the material to be removed from the cutting surfaces with each pass of the drill-bit. It is cool to use the sharpener at this point, with the chuck with its included cam, following the spring loaded cam follower.
While it appears un-nerving at first to see the chuck flopping around, its cool to see the original geometry re-ground on the cutting surfaces of the drill-bit.
How good a job of re-surfacing the drill-bit does it do? Drilling a hole in drill-rod 15 thousands undersized, to be reamed to a finished diameter of 1/2 inch, is a joy to see clean up upon making a pass with the reamer and not a trace of drill-bit marks remaining. I have seen factory drill-bits that drill a larger hole than the sized stamped on the shank of the drill-bit, and upon reaming there are drilling marks remaining.
Bottom line is, a good drill-bit sharpener such as this Darex, will duplicate the original geometery of the drill-bit and surpass it. The capacity of the Darex is 1/16th thru 3/4 inch.
For sharpening my #61 thru #80 drill bits, I use a Wishbone sharpener.