wood mortising bit Helical Mortising Bits 6pcs Set Professional Woodworking Tools! Helical mortising bits 6pcs set Ø6, 8,10,12,14,16/Shank straight MBH06160600Ø6, 8,10,12,14,16/Shank 13mm MBH06160613Ø6, 8,10,12,14,16/Shank 16mm MBH06160616 wood mortising bit