General; Torque Procedures - Cessna T182 Series Service Manual

MODEL 182 & T182 SERIES SERVICE MANUAL
1-6. GENERAL. This chapter deals with general tor-
(d) Since running torque will become less due
que and safetying practices used to ensure security of to nutbolt re-use (in accepted applications), this pro-
installation and prevent overstressing of components. cedure must be repeated each time.
Special torque values, when required, are specified (e) When necessary to tighten from bolt head,
with the specific component maintenance and installa- increase torque value by an amount equal to shank
tion instructions. torque (torque required to turn bolt when installed).
Measure with a torque wrench.
1-7. TORQUEING PROCEDURES. The importance of
correct application cannot be overemphasized. Under-
torque can result in unnecessary wear of nuts and
bolts as well as parts they are holding together. When Average
insufficient pressures are applied, uneven loads will
be transmitted throughout assembly, which may Dry torque required
result in excessive wear or premature failure due to
fatigue. Overtorque can be equally damaging because
b. Torque Values - Bolts and Nuts. (See Table 1-1.)
of failure of a bolt or nut from overstressing threaded
1. Tables included in this section do not apply to
areas.
the following exceptions:
a. Calculating Torque. There are a few simple, but
(a) Sheet metal screws should be tightened
very important, procedures that should be followed to
firmly, but with no specific torque value.
assure that correct torque is applied:
(b) Screws attached to nutplates should be
1. Calibrate torque wrench periodically to assure tightened firmly, but with no specific torque value.
accuracy; and recheck frequently. (c) Bolts, nuts, and screws used in control
2. When using a torque wrench adapter which systems and installations where required torque
changes distance from torque wrench drive to adapter would cause binding or interfere with proper opera-
drive. the indicated reading must be adjusted for tion of parts.
desired torque reading. (See Figure 1-2.) (d) Screws used with dimpled washers should
3. Be sure that bolt and nut threads are clean not be drawn tight enough to eliminate washer
and dry unless otherwise specified. crown.
4. Determine friction drag torque and add to
(e) Fasteners that have a specified torque in a
specified dry torque value to ensure proper bolt utili- specific nstallation.
zation. 2. The values shown in Table 1-1 are based on
(a) Hand-turn nut onto bolt until it stops. parts being clean and dry with no lubricants added.
(b) Using a torque wrench, measure runnin 3. Castellated nuts requiring cotter pins should
torque (torque required to turn nut on bolt).
be tightened to low torque value. Torque can be in-
(c) This running torque must be added to
creased to install cotter pin, but should never exceed
specified dry torque value to ensure proper bolt utili-
maximum torque value.
zation.
NOTE
EXAMPLE Self-looking castellated nuts, MS17825 and
Average running torque for a nut = 15 in.-lbs. MS17826, require a separate torque range.
Dry torque required
= 125 5 in.-lbs. These values are shown separately in torque
Final torque wrench reading
= 140 ± 5 in.-lbs. value tables.
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