· From 11 to 30, a tolerance of plus or minus 2 is
finish, coat or coats of paint and provides protection to
the surface against corrosion. For color-coding general
stenciling and more extensive repainting, refer to
· Above 30, a tolerance of plus or minus 5 is
chapter 2 of NAVSEA SW550-AA-MMI-010.
The most common primer used in the Mine Force
is zinc chromate. But zinc chromate paint dust is toxic;
Therefore, for a specified torque of 9
therefore, a respirator must be used during painting,
pound-inches, any applied torque between 8 and 10
sanding, and wire brushing operations. After the
pound-inches is acceptable. Torques specified in mine
primer coat or coats are dry, one or more finish coats
assembly procedures can be converted to or from
p o u n d - i n c h e s o r p o u n d - f e e t , a s n e c e s s a r y, t o
accommodate the increment graduations of the torque
wrench. This can be accomplished by multiplying
pound-feet by 12 or by dividing pound-inches by 12, as
All paints and thinners are hazardous materials.
Most of these materials are flammable or
combustible and can be hazardous to worker health.
When assembly instructions state to tighten
Avoid prolonged skin contact with paints and
mount, or secure an object (rather than giving a specific
thinners and wear approved respirator protection.
torque), fasteners must be tightened with the
Read the MSDS, available from your supervisor, for
appropriate tool without the use of excessive pressure.
the specific hazardous materials before you handle
Items, specified to be secured hand-tight, must never
or use them.
have tool pressure applied.
before use by exercising the wrench a minimum of
eight times at 60 percent of the rated torque range. This
Specific shop procedures are approved for use with
is accomplished by engaging the wrench with a test
explosive-loaded components during the maintenance
fastener and by applying the necessary pressure on the
and assembly of mines and mine components. These
handle until the audible torque-indicating mechanism
procedures must be followed to prevent personal injury
or damage to equipment and possible explosion.
Never attempt to apply a permanent torque value to
This section discusses tools, painting equipment,
a wrench by means of spot welding the micrometer at a
and battery storage.
given setting. That only damages the wrench and
P N E U M AT I C TO R QU E W R E N C H E S . --
Tools used in Mine Force shop procedures include
Pneumatic torque wrenches are adjustable power
torques wrenches and power tools. These tools are
torque tools that require a working pressure of 90
discussed in the following subsections.
pounds per square inch (psi) at the tool. When in proper
for both rundown and application of final torque to any
fastener. Final torque, as used here, is the value
To r q u e w r e n c h e s m a y b e e i t h e r m a n u a l o r
s p e c i fi e d i n m i n e a s s e m b l y a n d m a i n t e n a n c e
pneumatic. NAVSEA SW550-AA-MMI-010 gives
additional instructions in using torque wrenches.
For the proper use of a pneumatic torque wrench, it
MANUAL TORQUE WRENCHES.--Torques
must be connected to an air supply containing a
are generally specified in a single value, such as 18
moisture separator, an air-pressure regulator, and a
pound-feet or 12 pound-inches. In such cases, torque
means of introducing lubrication oil into the wrench.
tolerances are as follows:
Accordingly, the torque wrench must be connected to
· From 2 to 10, a tolerance of plus or minus 1 is
the simple system shown in figure 1-9 or to the spiral
flex system shown in figure 1-10.