PIPER
CHEROKEE SIX
SERVICE MANUAL
2-62.
TORQUE
WRENCHES.
Torque wrenches
should be checked daily and calibrated by
means of weights and a measured lever arm
to
make sure that inaccuracies are not present. Checking one torque wrench against another is not sufficient and
is not recommended. Some wrenches
are quite sensitive as to the way they are
supported during a tightening
operation. Any instructions
furnished by the manufacturer must
be followed explicitly.
When it is necessary to use a special extension or adapter wrench together with a torque wrench, a simple
mathematical equation must be worked out to arrive at the correct torque reading. Following is the formula to
be used: (Refer to Figure 2-19.)
T
=
Torque desired at the part.
A = Basic lever length from center of wrench shank to center of handle or stamped on wrench or listed for
that model wrench.
B = Length of adapter
extension, center of bolt
to center of shank.
C = Scale reading needed to obtain desired torque (T).
AxT
The formula: C =
A+B
EXAMPLE
A bolt requires 30 foot-pounds and a 3 inch adapter (one-quarter to
a foot or .25') is needed to get at it. You want to know what scale
reading it will take on a one-foot lever arm wrench to obtain the 30
foot-pounds
at
the bolt.
x 30 30
Remember, the 3 inch adapter must be projecting 3 inches straight
along the wrench axis. In general, avoid all complex assemblages or
adapters and
extensions of
flex joints.
A933
A
T
Figure 2-19. Torque
Wrench Formula
Added: 12/15/80
HANDLING
AND SERVICING
1D2
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