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TM 9-254
4-1.
Torque Wrench - Continued
d.
Adapter Length Compensation (figs. 4-5 and 4-6). When adapters are used that rotate about a center not
located at the center of the tang of the torque wrench, it is necessary to compensate for the additional length. An
extension will always increase the capacity of the wrench.
Figure 4-5. Torque Wrench - Straight Extension
(1)
When an extension adapter is used as shown in figure 4-5.
Let:
F
=
Force (pounds)
IT
=
Wrench length (inches) measured from the middle of handle to the center of the tang.
IA
=
Extension length (inches) measured from center of socket to center of drive square.
L
=
Effective lever length
L
=
IT
+ IA
Example:
(figure 4-5)
Assuming that the length of the torque wrench being used is 12 inches. The length of the extension is 2
inches. The torque setting of the wrench is 60 in. lbs.. The total torque applied at extension is 70 in. lbs.
Equation
TA
= TT X L or TA = 60 X 14 or TA = 70 in. lbs.
I
T
12
Where: TA
=
Torque applied at extension
L
=
IT (12 inches) + IA (2 inches)
TT
=
Setting of torque wrench (60 in. lbs.)
IT
=
Wrench length (12 inches)
4-4
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