This are special engraving bits for greater speed and feeds.

A gold colored film of Titanium Nitride with a hardness of approximately 85Rc is deposited on the tool which extends tool life by reducing friction and enables greater speeds and feeds. Coatings are for use at high speeds where the temperature is high enough to bring the coatings functional use into play.

This pack contains 10 x 1mm PCB drill bits for use in mini CNC machines. The shank is 1/8" diameter.