带护锥的(B型)中心钻  (摘自GB/T 6078.21998)  (mm)

d

1.00

(1.25)

1.60

2.00

2.50

3.15

4.00

(5.00)

6.30

(8.00)

10.00

d1

4.0

5.0

6.3

8.0

10.0

11.2

14.0

18.0

20.0

25.0

31.5

l

35.5

40.0

45.0

50.0

56.0

60.0

67.0

75.0

80.0

100.0

125.0

l1

1.31.9

1.62.2

2.02.8

2.53.3

3.14.1

3.94.9

5.06.2

6.37.5

8.09.2

10.111.5

12.814.2