TM 9-4910-638-14&P
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 of
boring as
seen
when looking directly toward the tool
Both these figures show the three different angles which are lapped on the end tool bit. These are numbers 1, 2
and 3.
FIGURE 5.
ROUGH BORING TOOL BIT
IN CUTTING POSITION
FIGURE 6.
LAPPING JIG FOR LAPPING ROUGH BORING
TOOL BIT IN POSITION 4R
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