ASTM E8 is one of the oldest and most popular tensile tests. Metals were one of the first materials tested for applications involving the prevention of boiler explosions. Andrew Carnegie created his fortune because the tensile strength of steel is stronger than iron. Specified under E8 are numerous calculations and additional measurements such as Poisson's Ratio which requires transverse strain measurements.
Grips and fixtures for E8 can vary. For round samples, the end could be butted(square), rounded(tapered), or threaded. A split collar can be used for the butted ends and a wedge grip with serrated V inserts can be used for the rounded ends.
The shoulder grip with exchangeable inserts is the ideal fixture setup for testing to ASTM E8. The fixture is designed to test button head style specimens, the same as shown in the virtualization to the left.
Flat samples are different and are usually held with wedge grips with serrated inserts. Samples with flat shoulders may also be fixed with a clevis pin if a hole is drilled through the specimen.