I’ve owned a Drill Doctor for a while and find it quite an asset to the shop. Recently, after sharpening a fairly large diameter bit with the DD I found it rubbing instead of cutting. I recognized this immediately as negative relief. In other words, the cutting edge, though sharp, was lower than the following edge. I had never had this issue grinding small bits, and a few attempts at fiddling with the DD settings proved fruitless. As much as I hate to admit it, I had misplaced the user guide, so off to the www.
My search brought me to the following video;
This addressed directly the issue at hand, and the girl with the French manicure pointed me towards the solution. First, I followed the directions to grind completely (spark out) which seemed to help, but only minutely. I then adjusted for greater relief as instructed, choosing the maximum setting. After grinding, the bit was just beginning to cut, and I could see some small chips lifting off, but the bit still rubbed when pushed.
As I had adjusted the bit’s maximum relief in the DD chuck, the third attempt I set using ” seat of my pants” adjustment. I rotated the bit manually just a small amount further in the chuck, maybe 1/8 of a turn. This did the trick, as after grinding the drill bit cut thru steel like butter.
This adds a little trial and error for setting up a bit in the DD, just something to be aware of.