Made especially to run 10mm Shank dowel drills and boring bits on a CNC machine. Accommodates the Flat area on the 10mm round drill bit shank, secure with the 2 set screws (M6), same method as on boring machines., #47636, (D) diameter 3/4, (D) shank 1/4, overall length (L) 2-5/32, D1 10mm, L1 1-1/16, 47636 10mm Shank dowel drill/boring bit adapter for CNC standard collet/tool holder