The Proving Ring

A proving ring is a device used to measure force. It consists of an elastic ring in which the deflection of the ring when loaded along a diameter is measured by means of a micrometer screw and a vibrating reed.  The proving ring was developed by H.L. Whittemore and S.N. Petrenko of the National Bureau of Standards (NBS), the precursor of the National Institute of Standards and Technology (NIST), in 1927.

• What is force?
• How did the proving ring come about?
• Design and construction of the proving ring
• Why measure force?
• Calibration of the proving ring

The author wishes to thank the Morehouse Instrument Company and the MTS Systems Corporation for contributing some of the graphics used in this homepage. Thanks are also expressed to Rick Seifarth of NIST Force Group for his help in locating some of the documents used in the preparation of this homepage.