STRAIGHT
SHANK
DRILLS
S O M T A P 1 2 C A T A L O G U E
48
Drill Terminology
... from previous page
STANDARD MORSE TAPER SHANK
To I.S.O. 296 DIN228 BS1660
No.
of
Taper
Fitting
line
Diameter
D
Diameter
d
Overall
Length
Max
L
D
1
a Max
L
1
Max
e
H13
b
Max
d
1
Taper /
mm
on Dia
Max
R
1
2
3
4
5
6
12.065
17.780
23.825
31.267
44.399
63.348
9.0
14.0
19.0
25.0
36.0
52.0
65.5
80.0
99.0
124.0
156.0
218.0
12.2
18.0
24.1
31.6
44.7
63.8
3.5
5.0
5.0
6.5
6.5
8.0
62.0
75.0
94.0
117.5
149.5
210.0
13.5
16.0
20.0
24.0
29.0
40.0
5.2
6.3
7.9
11.9
15.9
19.0
8.7
13.5
18.5
24.5
35.7
51.0
5.0
6.0
7.0
8.0
10.0
13.0
0.04998
0.04995
0.05020
0.05194
0.05263
0.05214
d b
R
e
D
a
L
1
D
1
d
1
L
HOW TO ORDER SPECIALS
MODIFIED STANDARDS
There are many instances when a special tool (a tool not found in the Somta catalogue or price list) can be
manfactured from a standard product. We call this a ‘modified standard’. Somta has both the capability
and capacity to offer this service which, under normal circumstances, means a short delivery time.
The following are typical drill modifications:
Intermediate Diameters
Standard sizes can be ground down to special diameters and tolerances.
Reduced Overall Lengths
Standard drills can be cut to special lengths.
Drill Points
The standard drill point angle is 118° included. This can be modified to any angle required. Many special
Continued on next page...
