GENERAL INFORMATION
1-15
torque wrenches in cases or separate padded drawers within a toolbox. Follow the manufacturer’s
instructions for their care and calibration.
Torque Adapters
Torque adapters or extensions extend or reduce
the reach of a torque wrench. The torque adapter
shown in (
Figure 13
)
is used to tighten a fastener that
cannot be reached because of the size of the torque
wrench head, drive, and socket. If a torque adapter
changes the effective lever length (
Figure 14
), the
torque reading on the wrench will not equal the actual
torque applied to the fastener. It is necessary to
recalibrate the torque setting on the wrench to
compensate for the change of lever length. When
using a torque adapter at a right angle to the drive
head, calibration is not required, because the effective
length has not changed.
To recalculate a torque reading when using a
torque adapter, use the following formula and refer to
Figure 14:
TW = TA×L
L+A
TW
is the torque setting or dial reading on the wrench.
TA
is the torque specification and the actual amount of torque that is applied to the fastener.
A
is the amount that the adapter increases (or in some cases reduces) the effective lever length as
measured along the centerline of the torque wrench.
L
is the lever length of the wrench as measured from the center of the drive to the center of the grip.
The effective length is the sum of L and A.
Example:
TA=20 ft.-lb.
A=3in.
L=14in.
TW=20×14=280=16.5 ft. - lb.
14+3 = 17
In this example, the torque wrench would be set to the recalculated torque value (TW = 16.5 ft.
–lb.). When using a beam-type wrench, tighten the fastener until the pointer aligns with 16.5 ft. –lb. In
this example, although the torque wrench is pre set to 16.5 ft. –lb., the actual torque is 20 ft. –lb.
