16mm Square Hole Drill Bits for Wood Woodworking Hole Saw Mortising Chisel Drill Bits(5/8 )

Specification: Material: High Speed Steel(HSS) Hardness: Up to HRC48~50 Size:6mm(1/5 ) - 25mm(1 ) Shape of hole: square rectangle Note: * Square hole drill can not be used on an electric drill drill square holes need to fit a square hole drill drilling (mortise and tenon machine) to use. * To avoid drill bits become overheated and get burned up due to fast rotary friction we suggest use cutting fluid to keep the bits cold during usage.