www.thedriller.com/articles/85317-percussion-drill-bit
Percussion Drill Bit
January 29, 2003
Percussion Drill Bit
The Concave (or Groundhog) drill bit by Epley has been designed for most general purpose drilling conditions. The design holds a very straight hole due to the tapered recess in the face of the bit. The recess causes a slight coring action, making the bit hold true, and the coring also promotes penetration and very positive air flushing of the hole. Epley Enterprises, Inc.
The Concave (or Groundhog) drill bit by Epley has been designed for most general purpose drilling conditions. The design holds a very straight hole due to the tapered recess in the face of the bit. The recess causes a slight coring action, making the bit hold true, and the coring also promotes penetration and very positive air flushing of the hole. Epley Enterprises, Inc.
