You can test torque multipliers in a few different ways:
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1. You can install an in-line transducer with a TS-1000 torque meter between the multiplier and the fastener for real-time torque display of the output of the multiplier (accurate to 1%).
2. You can use the TS-1000 with a bench mount transducer and test the multiplier on a test bench (accurate to .5%)
3. You can install a JETCO 0 - 2000 ft.lb mechanical dial type tool between the multiplier and the fastener (accurate within 3%).
Option 2. is the most accurate (.5%).
Option 1. will result in more accurate application of torque or will allow you to test at 1% accuracy.
Option 3. is the least accurate (3%) but is the most cost effective method.