Tension Link Calibration: Pin Size Is the Critical Variable (A case study in evidence-based force calibration decisions)
Tension link calibration accuracy hinges on one variable most end-users overlook: the pin. In this case study, Morehouse tested whether calibrating with the full shackle assembly actually matters, and the answer surprised a long-time customer. An undersized pin created a 1.72 % error at 50 000 lbf, while the shackle itself had zero measurable effect on the reading. Even two pins differing by just 0.005 in produced enough variation to fail a common tolerance band more than half the time.
The implications go beyond measurement. The same pin variables that drive indicated error also affect structural integrity, meaning tension link calibration decisions carry real safety consequences. Morehouse used these findings to build a practical framework, covering pin selection, orientation documentation, and when shackle inclusion is actually worth the cost, that any tension link user can apply. The full case study walks through each test, the data behind the recommendations, and the clevis setup guidance that ties it all together.
