Three Benefits of Installing a Threaded Adapter on Shear Web Load Cells
#1. The output of the load cell is more repeatable - When forces are applied to the load cell, the values obtained during calibration should repeat within the expected performance of the load cell. Additional error sources from the different hardness of material, misalignment, and temperature still apply.
#2. The technician can concentrate on alignment and other things instead of worrying what adapters will yield a reproducible measurement - Those who do not lock an adapter into place will have to make sure the thread engagement and fit is the same as the lab that calibrated the device.
Note: Do not remove the threaded adapter as it will make the calibration void. These adapters are locked in at approximately 140 % of the rated capacity. Removal of the adapter can damage the load cell if enough torque is applied and getting the adapter to the same position it was at before removal is highly improbable.
#3. The load cell will repeat better when rotated per ASTM E74 – When a load cell is calibrated in accordance with ASTM E74, the load cell is positioned at orientations of 0 degrees, 120 degrees, and 240 degrees. Installing a threaded adapter improves the reproducibility of the load cell. When we tested this on the same load cell, we observed an ASTM LLF of 0.32 LBF with a threaded adapter installed versus 0.553 LBF without the adapter installed. The load cell with the threaded adaptor installed had a 42 % improvement in reproducibility.
Three Disadvantages of not Installing a Threaded Adapter on Shear Web Load Cells