a signal mechanism automatically issues an
and standards will prevent this. Torque
audible click. Next the handle releases, or
" b r e a k s , " and moves freely for a short
use ONLY calibrated torque wrenches.
distance. You can easily feel the release
and free travel and know when the torquing
Types of Torque Wrenches
process is complete.
The procedure for using the deflecting
beam and the dial indicating wrenches is
The three most commonly used torque
wrenches are the deflecting beam, dial in-
however, you have to hold the torque at
dicating, and micrometer setting types (fig. 3-14).
the desired value until the reading is steady.
When using the deflecting beam and the dial
indicating torque wrenches, you read the torque
on a dial or scale mounted on the handle of the
Torque values are expressed in pound-
The torque wrench you will probably
inches (lb-in.) or pound-feet (lb-ft). One pound-
use is the micrometer setting. This type is
inch (or 1 pound-foot) is the twisting force
of 1 pound applied to a twist fastener (such
easier to use because you do not have to
as a bolt or nut) with 1 inch (or 1 foot)
watch a dial or pointer while using the
of leverage. This twisting force is applied
to the fastener to secure the components.
When you are working with or reading torque
To use a micrometer setting wrench, un-
lock the grip and adjust the handle to the
values, they are usually expressed in inch-
desired setting on the micrometer scale. Then,
pounds (in.-lb) or foot-pounds (ft-lb).
relock the grip. Install the required socket
A manufacturer's or a technical manual
or adapter to the square drive of the handle.
generally specifies the amount of torque you
Place the wrench assembly on the nut or
should apply to a fastener. To assure getting
the correct amount of torque on the fastener,
bolt and pull in a clockwise direction with
use the wrench according to the manufacturer's
a smooth, steady motion. (A fast or jerky
instructions. When using an adapter (such
motion results in an improperly torqued unit.)
as a crowfoot wrench) with a torque wrench,
When the applied torque reaches the torque
value, which is indicated on the handle setting,
you must calculate the correct adapter torque.
Figure 3-14.--Torque wrenches.