Bests & Worsts Reviews from Amazon

I needed to drill a 17/64" hole in a grade 5 1/2" bolt. I owned three 17/64" cobalt drill bits. Not one was sharp enough to make more than a dimple in the bolt... with much smoke and screeching at that. As I am a fan of expensive solutions to simple problems, I purchased this item. After 10 minutes of video tutorial and 3 minutes of futzing, my drill press was turning out these beautiful shavings from the first drill bit I sharpened. Although I haven't got the geometry or technique perfect yet, with a little more practice, this item will pay for itself handily.