... Inc.)
12 ¡
84 ¡
15 6¡
(b)
FIGURE 8 .17 : (a) Indexable drills using Trigon inserts. (b) A Trigon insert and holder. (Courtesy Komet of
America, Inc.)
(a)
Chap. 8: Drills & Drilling Operations
10
Tooling ... in
Figure 8. 8a, and a counter- sinking tool
with two machined holes is shown in
Figure 8. 8b.
Centering: Center drilling is used
for accurately locating a hole to be
drilled...
... O
A
O
B
O
C
O
D
O
E
10 O
A
O
B
O
C
O
D
O
E
11 O
A
O
B
O
C
O
D
O
E
12 O
A
O
B
O
C
O
D
O
E
13 O
A
O
B
O
C
O
D
O
E
14 O
A
O
B
O
C
O
D
O
E
15 O
A
O
B
O
C
O
D
O
E
16 O
A
O
B
O
C
O
D
O
E
17 O
A
O
B
O
C
O
D
O
E
18 O
A
O
B
O
C
O
D
O
E
19 ... O
A
O
B
O
C
O
D
O
E
78 O
A
O
B
O
C
O
D
O
E
79 O
A
O
B
O
C
O
D
O
E
80 O
A
O
B
O
C
O
D
O
E
81 O
A
O
B
O
C
O
D
O
E
82 O
A
O
B
O
C
O
D
O
E
83 O
A
O...
... E
11 2. B
11 3. D
11 4. D
11 5. D
11 6. A
11 7. D
11 8. E
11 9. E
12 0. B
12 1. E
12 2. C
12 3. A
12 4. A
12 5. D
12 6. E
12 7. D
12 8. B
12 9. C
13 0. C
13 1. D
13 2. C
13 3. B
13 4. B
13 5. ... D
13 6. D
13 7. A
13 8. E
13 9. B
14 0. E
14 1. C
14 2. E
14 3. D
14 4. D
14 5. D
14 6. B
14 7. C
14 8. B
14 9. A
15...