TM 5-3825-270-23&P
0218
SCOPE - Continued
recommended torque, it should be disregarded and the nut tightened to the recommended torque value. If the torque
is 113 or more of the recommended torque, it should be added to the recommended torque. Example: The
recommended torque is 50 to 70 Ib-in. (6 to 8 Nm). The torque at one turn from seating is 30 lb-in. (3 Nm). The
correct torque wrench reading would be 80 to 100 Ib-in. (9 to 11 Nm).
4. Retorquing Fasteners. Procedures intended for installing metal fasteners can cause incorrect readings when
used to check or retorque already installed fasteners during maintenance. Before checking or retorquing an already
installed threaded fastener, first mark the fastener and its companion components so the marks are in line. Second,
back it off a 1/4 turn to loosen it. Torque it to the specification with an even steady pull on the torque wrench. The
marks should be in line; if not, the marks will indicate the fastener was under- or over-torqued.
5. Standard Torque Charts. Standard torque charts have been established for dry and wet torque conditions.
Surface variations such as thread roughness, scale paint, lubrication (oil, grease, etc.), hardening, and plating may
alter these values considerably. Tables 2 and 3 are standard torque charts.
6. To find the grade of the screw that is to be installed, match the markings on the head to the correct picture of
CAPSCREW HEAD MARKINGS in Tables 2 and 3. Manufacturer's marks may vary.
Table 2. Torque Limits - SAE Standard Fasteners.
QUALITY OF
INDETERMINAT
MINIMUM
MEDIUM
BEST
MATERIAL
E
COMMERCIAL
COMMERCIAL
COMMERCIAL
SAE Grade
1 or 2
5
6 or 7
8
Number
Capscrew
Head Markings
Manufacturer's
Marks May
Vary
These are all
SAE Grade 5 (3
line)
CAPSCREW
TORQUE
TORQUE
TORQUE
TORQUE
BODY
LB-FT (NM)
LB-FT (NM)
LB-FT (NM)
LB-FT (NM)
SIZE IN. -
THREAD
1/4
20
5
(7)
8
(11)
10
(14)
12
(16)
28
6
(8)
10
(14)
14
(19)
5/16
18
11
(15)
17
(23)
19
(26)
24
(33)
24
13
(18)
19
(26)
27
(37)
3/8
16
18
(24)
31
(42)
34
(46)
44
(60)
24
20
(27)
35
(47)
49
(66)
7/16
14
28
(38)
49
(66)
55
(75)
70
(95)
20
30
(41)
55
(75)
78
(106)