Lesson 5/Learning Event
IDENTIFY TORQUE WRENCHES BY TYPES AND USE
A torque wrench is used for work requiring a particular force (torque). It
has a measuring device that indicates the amount of torque or twist being
applied to a nut or bolt.
In much of today's machinery, engineers have
carefully worked out the degree of tightness to which nuts or bolts should
be tightened. If they are not tightened enough, they may loosen in service.
If they are tightened too much, the bolts or machine parts may be strained
excessively and break. In either case, the result could severely damage the
machine. The torque wrench allows nuts and bolts to be tightened just the
Torque can be defined as a twisting force.
A one-pound pull on a 1-foot
wrench (center of bolt to point of pull) equals 1 foot-pound. Force times
distance equals torque.
The formula for determining torque would be as
(F x D = T) or 1 pound x 1 foot = 1 foot-pound of torque
When an extension (adapter) is used to lengthen a torque wrench, the
effective length is increased.
Increasing the effective length of the
wrench changes the actual torque reading on the dial.
To calculate the
actual torque, the following formula may be used:
A - Torque reading on dial
B - Length of torque wrench without adapter
C - Length of adapter