Thread: Drill grinding weirdness

That drill has a thicker center section and a different flute profile ground into it, the center section generally gets thicker as a drill gets shorter or some drills are just designed stronger in that center part (most cobalt for example)
If you are going to sharpen it in your jig you will have to rotate your start point on both sides so that the non cutting center line diverges further away from 90deg to the cutting faces.....or as above other posts...some jig type grinders will do a center point tho.

Or simplest of all whack a 3-6mm pilot threw first then the center doesnt matter