Regrinding Systems
Regrinding Instructions for Gun Drill N-8 & Half Round Drill HA-1:
Grinding
- Position horizontal register at +30º , (half round drills at +20º), vertical register at +12º. Grind until all wear is removed.
- Position horizontal register at +29º, (half round drills at +19º), vertical register at +20º. Grind to establish the primary relief width of approximately 5% of the diameter.
- Position horizontal register at -20º, (half round drill at -15º), vertical register at +12º. Grind to establish the point position width of drill diameter. (Dia./4).
- Position horizontal register at 0º, vertical register at +25º. Grind front clearance until the triangle created reaches the rear edge of the primary relief.
- For gun drill only. Position horizontal register at -25º, vertical register at -12º. Grind until the triangle formed reaches the center of the tip "V".
- Remove drill and freehand a periphery chamfer around the radial surface at approximately 20º, stopping just short of the primary relief.
Important Announcement concerning the DM-43 and DM-43-A availability.
DM-43
DM-42
DM-43

More about the DM-43
Important Announcement concerning the DM-43 and DM-43-A availability.
DM-41 and DM-42
A regrind fixture for tool and cutter grinding machines.
More about the DM-41
More about the DM-42
DM-41 Literature
DM-42 Literature
Either style of regrinding fixture can be used to resharpen half round and/or single flute drills, or take advantage of Sterling Gun Drills' resharpening service with fast turnaround. Please also view the Regrinding Section.
TWINMASTER™ - Regrinding Information

More about the TWINMASTER™ drills