Installation, Operation and Maintenance Manual
CD, HL & NC Ranges of Dri-Prime
®
Pumps
42
95-0019-0000 Iss 11
11.5 Spanner Torques
The following tables give the recommended tightening torques for general purpose metric and UNC fasteners. They are to
be used only when the joint is metal to metal (i.e. no joints or gaskets) and no special figures (e.g. for impeller retaining
bolts) have been quoted.
Table 1 Metric Fasteners
Steel
Stainless
Torque
(N-m)
Thread Size
Nuts & Bolts
Nuts on Studs
All
M6 x 1.0
11.7
4.6
9
M8 x 1.25
28
11
22
M10 x 1.5
56
22
44
M12 x 1.75
98
38
76
M16 x 2.0
244
95
187
M20 x 2.5
476
185
364
M24 x 3.0
822
320
629
M30 x 3.5
1633
633
1240
Table 2 UNC Fasteners
Steel
Stainless
Torque
(N-m)
Thread Size
Nuts & Bolts
Nuts on Studs
All
¼” - 20
13.5
5.4
10.5
5/16” – 18
27.1
10.5
21.0
3/8” – 16
48.8
20
37.8
7/16” – 14
74.6
30
57.8
½” – 13
122
48
94.6
5/8” – 11
237.3
95
183.9
¾” – 10
420.4
167
325.8
7/8” – 9
664.4
266
514.9
1” - 8
1003
401
777.3
Table 1 figures are for Metric fasteners to BS3692. Steel fasteners: - Grade 8.8 for bolts, Grade 4.6 for studs, Grade 10 for
nuts; Stainless Steel fasteners: - Grade A2.
Table 2 figures are for UNC fasteners to BS1768 Steel fasteners: -Grade S and Grade 3 for nuts; Stainless Steel fasteners:
- Grade A2.
If steel fasteners are of dissimilar condition then the figures Table 1 or Table 2 must be multiplied by those in Table 3.
Table 3 Correction factors
PLATING CONDITION OF BOLT
BLACK ZINC
PLATING CONDITION OF
NUT
BLACK
1.0 0.9
ZINC
0.9 0.8
11.6 Thread Locking Compounds
Item Recommended
compound
Characteristics
Mechanical seal shaft sleeve
locking screws
Loctite 243
Suitable for stainless steel fasteners
Temperature range up to 150°C
Medium strength
Assembly time 15-30 minutes
