Wintersteiger's Drill Bits mount ski bindings with a professional ski shop quality. The 4.1mm drill bit works well with most drills and comes with 25 hole plugs. This drill bit is 9.5mm long and has a 4.1mm diameter. What size drill bit do I need to mount my ski bindings? Check the ski you are working on. Most skis have the recommended drill bit size printed right on them.