Piper COMANCHE PA-24-180 Service Manual page 42

PIPER COMANCHE SERVICE MANUAL
2-lOa. 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 theformula to
be used: (Refer to Figure 2-8a.)
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).
The formula: C = Ax T
EXAMPLE
A bolt requires 30 foot-pounds and a 3 inch adapter (one-quarter of
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
C I x 30 or C = 30= 24 ft-lbs
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
Figure 2-8a Torque Wrench Formula
HANDLING AND SERVIC
HANDLING AND SERVICING
REVISED: 11/1/82
1B18