"Originally bought the Digger set as this is better value. Lasted quite well until used on some green oak, which proved to be a little too tough for the pilot drills. Thought I could just replace the pilot with another drill but the originals had a flat on one side of the shank to stop spinning unlike a normal drill. So ended up buying this item to replace broken bits. The digger sets are simple to use and will last with careful use, particularly in harder woods."