This may be the last version of our Newsletter in this format. This newsletter discusses our Portable Calibrator, LAC and has an article on measurement risk.
Features: New Calibration Certificates and QR Codes; Top 3 ASTM E74 Calibration Mistakes; Upcoming Events – Announcements and Dates
Features: Designing Force Adapters for Calibration; Quick Change Tension Adapters for Calibrating Machines; Upcoming Events – Announcements and Dates; Meet Our Staff - James Wagner, Chief Engineer
Features: 2-Bar Versus 3-Bar Universal Calibrating Machines; ASTM E74 Calibration – Simplified step-by-step instructions; Upcoming Events – Announcements and Dates
Features: Tips from the Cal Lab - SPC – Statistical Process Control in the lab; Good Measurement Practice – Keep your system in control with a 5 in 1 solution; Calibration Intervals – by Phil Smith; Upcoming Events – Announcements and Dates
Features: Load Cell Troubleshooting – Morehouse 7 Step Load Cell Troubleshooting Guide; Potential Measurement Error – Tension Links; Meet the Morehouse Staff – Barry Cook (Lab); Training Workshop – Announcements and Dates
Features: Lean Tips – Setup Reduction; Potential Measurement Error – Unbolting Load Cells May Not Product Repeatable Results; Meet the Morehouse Staff – William Lane (Design Engineer); “Specifying Accredited Services” – Column by Phil Smith
Features: Lean Tips - 5S or 6S; Potential Measurement Error - 4 wire versus 6 wire; Meet the Morehouse Staff - Brian Ruppert (Machine Shop Supervisor); "Single Measurement Bliss" - Column by Dilip Shah discussing the problems with a single measurement
Features: Tips from the calibration lab - Point of Use to Save Time; Potential Measurement Error - Loading Through Bottom Threads in Compression; History of Morehouse - A detailed history from the 1920's through 2015; Oops! I severed my Cable Again - An article about switching cables
Several organizations and publications reference or insist on maintaining a 4:1 Test Uncertainty Ratio (TUR) without understanding the level of risk that they may be subjecting themselves to. The general thought is if the lab performing the calibrations has standards at least four times better then what they are calibrating that everything is good. This paper discusses TUR, PFA Risk, and why the location of the measurement matters. We will discuss two managed risk guard banding methods (5 & 6) found in the ANSI/NCSL Z540.3 Handbook. We will show that a 4:1 TUR is not enough and can result in a 50 % risk.
Want to learn more about force measurement errors and the impact the wrong adapters can have? The wrong adapters can produce measurement errors up to 20 times that of when the instrument was calibrated. This technical paper provides greater detail on adapters for compression and tension calibration of load cells, mini load cells, washer load cells, s-beam, tension links, multi-axis, hand-held for gauges and other force measuring instrumentation. It goes into detail about to improve your force calibrations with the proper adapters.
Morehouse has been performing both ASTM E74 and ISO 376 calibrations for more than fifteen years. We have been calibrating in accordance with the ASTM E74 standard since its introduction in 1974, and performing ISO 376 calibrations since sometime in early 2000. Until recently, we assumed that the rest of the world and force community knew that the standards were completely different and that either standard could not be substituted for another. This paper explains those differences in more detail.
Measurement decision risk as probability that an incorrect decision will result from a measurement. Are you telling your customers instrument passes without considering measurement uncertainty? If taken to court, are your measurement defensible? This paper examines the proper way to make statements of compliance.
Having troubles understanding measurement uncertainty and how to put together a budget? This paper examines all of the components required to put together a full calibration and measurement capability (CMC) reviewed by Accreditation Bodies for your scope. This is a guide to calculating force measurement uncertainties and was published in Cal Lab magazine.
Article written by Henry Zumbrun for Cal lab Magazine.
What you need to know about dual range calibrations. Article from Test Magazine May 2016 issue.
Article in test magazine from Oct-Nov 2015 issue.
There is not a difference in repeatability and reproducibility between a 2 bar and a 3 bar Universal Calibrating Machine
Written and published in Cal Lab magazine April 2016
Article published in Quality Digest written by Henry Zumbrun (Morehouse Instrument Company).
Several organizations and publications reference or insist on maintaining a 4:1 Test Uncertainty Ratio (T.U.R.) without understanding the level of risk that they may be subjecting themselves to. This blog examines the probability of false accept and why the location of the measurement may be more important than T.U.R.
This blog is going to discuss the Morehouse Concrete Compression Machine Calibration kit and the potential error sources associated with using material with a different hardness than what the system was calibrated with. Morehouse has created a kit to minimize the common compression error sources while providing a lightweight portable solution with an ASTM verified range of forces of better than 400 lbf through 600,000 lbf (660,000 lbf is possible) for calibration of concrete machines to ASTM E4.
Has anyone ever wondered if there is a difference in calibration results if the time interval between successive loadings is changed? Is faster better and does it matter if the calibration takes 10 minutes on an automated machine pictured in figure 2 below, or two to three hours at NIST or a comparable lab with deadweight calibration systems?
This blog discusses the most important attributes of great force calibration machines such as being plumb, level, rigid, and square and error sources associated with not having a machine that has these attributes.
Morehouse 2,000 lbf Tensiomenter calibrator to calibrate Cable Tensiometers Safely, Load Cells, Crane Scales, Hand-Held Force Gauges, Dynamometers, and More.
Any organization that is accredited must account for the uncertainty of their standards. The following are guidelines to assist in calculating the measurement uncertainty for dead weight primary standards.
This post describes various force standards that are often used to calibrate force sensors and other devices. It discussed in detail the advantages of deadweight machines for the best calibration results. It then goes into detail about what it takes to calibrate a load cell properly.
Morehouse Training at NCSLI 2018 in Portland. We will be teaching two tutorials, one on force and one on torque as well as presenting at Session 5A and the Airline Committee meeting.
Load cell stability can potentially consume your uncertainty budget, cause the force measuring device to be out of tolerance, cause all measurements between the last calibration and the current calibration to be recalled, raise the accuracy specification of the system. This post covers what instability is and ways to potentially reduce instability.
Some ISO 17025 accredited labs performing torque calibrations may not entirely be considering the effect on the uncertainty from Torque Measurement Error from Applied Force Direction (cosine error)