TMA, there is a book,the complete guide to sharpening by Lie Nielsen that might have the information you need for the proper way to sharpen drills.I had a posted a question on sharpening of corner chisels and one of the experts on this web emailed me that page of the book.Hopefully he will do the same for you.I am no expert but this works for me.I use a finepointed file that is 1/4" wide. Sharpen the threads on the point so it pulls the bit into the wood.File only the inside of the spurs or tangs and then I file the cutting edge and back bevel.I hope this works for you, and maybe we can get more input from some other members. John