The tool bits used are tipped with Tungsten Carbide. TUNGSTEN CARBIDE IS AN EXTREMELY
HARD AND BRITTLE SUBSTANCE AND MUST, THEREFORE, BE HANDLED WITH GREAT
CARE AT ALL TIMES.
Figures 5 and 8 show the tool bit (greatly enlarged)
in the roughing and finishing operations
boring as seen when looking directly toward the tool face.
Both these figures show the three different angles which are lapped on the end of the tool bit.
These are numbers 1, 2 and 3.
ROUGH BORING TOOL BIT
IN CUTTING POSITION
LAPPING JIG FOR LAPPING ROUGH BORING
TOOL BIT IN POSITION 4R
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