The Design and Construction of Tensile Test Gripping Assemblies

The goal of this project was to design, manufacture, and test a pair of cheap gripping assemblies with mount adapters to the Instron TT-C tensile testing machine, which is currently out of service in the Materials Laboratory of Central Washington University’s Hogue Technology Building. The gripping assemblies would enable tensile, or pulling force, tests on tensile specimens up to 20,000 lbs, being able to test high carbon steel. The gripping assemblies and mounting adapters were designed and manufactured completely by a Central Washington University Mechanical Engineering Technology student who used the cumulative knowledge gained from engineering analysis and manufacturing courses over the span of his four years at Central. All design and manufacturing were done using the Central Washington University facilities and laboratories with the exception of heat treatments which were outsourced. It is estimated that the initial device construction will cost $771.00 and 440 man hours. Most gripping assemblies in industry cost anywhere between $6,000 and $15,000 for assemblies with a 20,000 lb load capacity. The design of the gripping assemblies is simple with no luxury of hydraulic, pneumatic, or mechanical clamping capabilities. The manufacture of the initial pair of gripping assemblies was unreasonable and robust due to limitations governed by the capabilities of Central Washington University’s lab facilities which also added unreasonable hours to the amount of man hours required. In common industrial factories/warehouses owned by testing machine manufacturers, the amount of man hours would be significantly less