If You Do Not Have Uncertainty, You Do Not Have a Calibration: A Guide to Calibration Measurement Uncertainty A Price Tag That Just Says "Some" You take your truck to the shop. The mechanic looks under the hood and says the repair will cost "some." You ask how much is some. He shrugs and hands […]
Do Load Cells Wear Out? What Ten Years of ASTM E74 Data Say About Load Cell Aging In short: no, not the good ones. Across 16 703 deadweight ASTM E74 results on shear web cells, the median lower limit factor is 0.0055 % of capacity in the first year we see a cell and 0.0048 % eight […]
The Transfer-Standard Penalty: The Same Instrument, Two Calibration Certificates, and What Changed Between Them (Deadweight Calibration vs Transfer Standard) In short: we found 17 customer instruments with a stated accuracy of 0.1 % of full scale or better that Morehouse has calibrated both ways since 2018, on a deadweight machine in some years and on a […]
Pancake Load Cell vs S-Type Load Cell: What Over 11 000 Calibrations Say About Which One to Buy In short: on deadweight ASTM E74 calibrations from 300 lbf to 120 000 lbf, the pancake (shear web) load cell runs at a median lower limit factor of 0.005420 % of capacity and the S-type (S-beam) at […]
Load Cell Temperature Compensation: Why a Load Cell Has to Earn Its Temperature Rating Check your tire pressure in a cold garage, then drive two hours on a hot highway and check it again. The number went up. Nothing leaked in and nothing leaked out. The tire is the same tire; only the temperature changed. […]
Load Cell Testing: How a Prototype Earns Its ASTM E74 Certificate How Morehouse approaches load cell testing on a new prototype, from the temperature chamber to the deadweight machine to an ASTM E74 calibration, and why one aluminum prototype has us excited. “Remember, kids, the only difference between screwing around and science is writing it […]
Where One Term Ends and the Next Begins, Decision Rules FAQ - Quick Answers on TUR, Guardbands, and Risk ("Part 8") Seven parts generate questions. Here are the ones that show up most, with short answers and a pointer to the part that carries the long version. It’s also the credits section, hence part 8 […]
Where One Term Ends and the Next Begins, Part 7 of 7: PFA and PFR Explained: Probability of False Accept and Reject A kicker makes 97 % of his field goals from the 35-yard line. This kick is from the 35, and it sails wide. Based on the population data alone, you would have said it […]
Where One Term Ends and the Next Begins, Part 6 of 7: Guardband Calculation Ask a field goal kicker about the wind. The goal posts never move. But a kicker facing a strong crosswind aims inside the upright to compensate for the drift he knows is coming. That aim point is the acceptance limit. The […]
Where One Term Ends and the Next Begins, Part 5 of 7: Decision Rule Selection - Which Rule to Use and When "Would you tell me, please, which way I ought to go from here?" Alice asks the Cheshire Cat. "That depends a good deal on where you want to get to," the Cat says. […]
Where One Term Ends and the Next Begins, Part 4 of 7: Test Uncertainty Ratio (TUR) - A Screen, Not a Decision Rule Figure 7. Consumer risk against accuracy ratio. The curve passes through roughly 1 % consumer risk near a 3:1 ratio, the relationship Hayes worked on. Jerry Hayes of the United States […]
Where One Term Ends and the Next Begins, Part 3 of 7: Bias vs Uncertainty - Why Compensation Is Not Padding Picture two bathroom scales. The first reads 2 lb heavy every single time, dead consistent. The second is perfectly centered on average but jumps around by a pound either way. The first scale has a […]
