Standard Practice - Airframe - Piper CHEROKEE WARRIOR PA-28-151 1995 Maintenance Manual

PIPER CHEROKEE WARRIOR SERVICE MANUAL
2-89.

STANDARD PRACTICE - AIRFRAME.

2-90. TORQUE WRENCH: 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 for-
mula to be used: (Refer to Figure 2-13.)
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).
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.
R e m e m b e r, 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.
Revised: February 28, 1995
The formula: C = A x T
A + B
EXAMPLE
C = 1 x 30 or C = 30 = 24 ft.-lbs.
1 + .25 1.25
Figure 2-22 . Torque Wrench Formula
1D12
Island Enterprises
HANDLING AND SERVICING