SM0486
(1) When you use the torque tester to check a torque wrench, you should
proceed as follows:
Mount torque wrench on torque tester.
Pull torque wrench slowly and smoothly to desired torque.
Check reading of torque wrench against reading of torque tester.
Repeat the two steps directly preceding this one at least twice.
(2) An average of three or more readings gives the amount of error
introduced by the torque wrench, and the variation between readings shows whether
or not you are pulling the torque wrench correctly. This completes our discussion
of the Sweeney type torque calibrators.
Now compare the Sweeney operating
principle with the construction and operating principle for the Baldwin type torque
calibrator.
8.
Baldwin Type Torque Calibrator. If your shop is equipped with a model 4 torque
wrench tester, various types of torque wrenches and handles can be calibrated
quickly and accurately. The tester is designed for preset (clickoff or breaking)
type wrenches.
You can test beam, flexible hose, and other types of torque
wrenches on this equipment if the proper adapters are available and the wrench is
within the equipment range. The tester accommodates wrenches with square drives up
to 1 inch in size with pressure capabilities up to 2000 foot-pounds. To increase
your ability in the use of the tester, you must learn more of the instrument's
torque application system and the instrument's torque measuring system.
a. Torque application system. Figure 9 is included so that you can identify
the external controls and components of the Baldwin 4 tester as the torque
application system is discussed. The Baldwin 4 torque calibrator, shown in Figure
9, is designed around the Baldwin-Lima Hamilton SR-4 strain gage transducer. The
strain gage transducer is a sensing device which uses the basic strain gage
principle for the measurement of forces, torques, and pressures.
In the model k
tester, force is applied to the stationary-held torque wrench through the SR-4
transducer (torque cell).
At the same time, the result of the applied force
(torque) is continuously indicated on the equipment dial, which is calibrated in
inch-pounds and foot-pounds.
When you compare the torque indicated on the dial
when the wrench slips with the torque wrench settings, you can determine the
accuracy of the torque wrench scale.
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