These machine bits have two wings, two scribers and a centre point. Tungsten carbide tipped for extensive drilling of particle boards, and plastics of soft to medium density. The scribe gives a very clean entrance hole. Not for use on hard dense materials such as laminate covered board, phenolic Tufnol, Wareite and GRP. For such materials, choose from Group 421 tools which have no scribers. For use in drilling machines only.