Lesson 5/Learning Event
CARE OF TORQUE WRENCHES
A torque wrench is a precision measuring instrument that accurately limits
the torque applied to a fastener. Do not use the torque wrench as a general
purpose turning tool.
When using a torque wrench, observe the following
rules:
1. Never use a micrometer torque wrench in a position below the minimum
torque setting on the scale.
However, when storing a micrometer
torque wrench, always adjust the handle to its lowest setting.
2. Never use the torque wrench to tighten a fastener to a higher torque
than the maximum reading on the scale.
3. Never use a torque wrench on a fastener that has been tightened with
a wrench or socket.
For an accurate torque reading, the final
tightening must be done with the torque wrench.
4. A torque wrench has a recommended calibration interval. Most torque
wrenches are guaranteed to be accurate within four percent.
To
ensure that the wrench is always this accurate, have it checked at
specified intervals by the manufacturer.
5. Examine and try torque wrenches. Note how varying amounts of pull
on the wrench handle register on the wrench dial. A torque wrench
should be pulled evenly and steadily; it should not be jerked.
6. Threads should be cleaned and lubricated before a nut or a bolt is
tightened.
This reduces thread friction and results in more
accurate tightening.
7. Take special care of the torque wrench to avoid damaging it or
ruining its adjustment. Keep it clean and oiled; put it away in a
protected place after each use.
METRIC SYSTEM VERSUS US CUSTOMARY SYSTEM
Today, knowing how to convert measurements from the US customary system to
the metric system is very important.
Kilograms (kiloponds) or newtons express force in the metric system.
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