1/2" Impact Comparison: IR VS. Aircat

[rlitman]

There is something odd about this youtube film “AIRCAT 1200-K vs IR 2135TiMAX Torque Test”



The aircat has a max rated working power of 900 ft lb, and the IR 550 ft lb.

But the measuring instrument reads 568 ft lb for the aircat, and 410 ft lb for the IR.



So, the measurement is 332 ft lb off from the aircats rated powers, and the measurement is 140 ft lb off for the IR gun.



Why is there so much difference between the rated numbers and the measured numbers. Broken measuring instrument or instrument not suitable for this type of impact? Is the instrument calibrated? Are the rated numbers just commercial numbers?

Because the "max" torque ratings are about as inflated as compressor, shop vac, and lawnmower horsepower.

 

[Marlin]

There is something odd about this youtube film “AIRCAT 1200-K vs IR 2135TiMAX Torque Test”

The aircat has a max rated working power of 900 ft lb, and the IR 550 ft lb.
But the measuring instrument reads 568 ft lb for the aircat, and 410 ft lb for the IR.

So, the measurement is 332 ft lb off from the aircats rated powers, and the measurement is 140 ft lb off for the IR gun.

Why is there so much difference between the rated numbers and the measured numbers. Broken measuring instrument or instrument not suitable for this type of impact? Is the instrument calibrated? Are the rated numbers just commercial numbers?

There are different ways of testing impacts, the tester that is shown is an electronic "Skidmore" which is a strain gaged shaft that measures the individual torques spikes or blows that the impact puts out, so the number achieved only represents the highest blow achieved over the samping time. Most catalog numbers for impacts are arrived at by actually tightening a fastener over a span of time (ussually 10 sec) and then measuring the torque that as achieved, this number if greater than that of the single blows measured on the electronic tester.