Instruments for testing metals have been manufactured commercially since the 1900's, and there are several manufacturers of testing equipment that meet the requirements of ASTM E23. Over the years, the basic physical characteristics of the test machine have stayed the same, but the means of data acquisition have changed significantly and, as a result, many types of equipment, ranging from analog dial & pointers to digital readouts to computer interfaces, are found in various labs throughout the country.

Just because equipment is old doesn't mean that it is obsolete. It doesn't mean it is acceptable for use either since wear and tear take their toll over the years and some machines were manufactured before strict adherence to the specifications in ASTM E23 was deemed to be critical. There is no hope of ever getting accurate results if the equipment isn't operating according to the specification, therefore it is strongly recommended that the impact tester is calibrated and/or verified by an accredited calibration service at regular intervals.