Instron Extensometer ASTM E-83 Calibration by Instru-Met Extensometer calibration to ASTM E-83 and ISO 9513 Instru-Met celebrates its 40th  year continuing its calibrations of Extensometers to the ASTM E-83 Standard and  ISO 9513. Instru-Met uses precision devices offering some of the best accuracies in the business.We also calibrate Load cells to ASTM E-4 using precision equipment calibrated to ASTM E-74 with dead weights to insure the lowest measurement uncertainty.