ASTM D143 - 14: Standard Test Methods for Small Clear Specimens of Timber.

ASTM D143 Tensile Testing Perpendicular to the Wood Grain. which describes the size and shape of the grips used for tension testing wood specimens perpendicular to the grain. In the test, a timber specimen is cut into shape and placed into the fixture. A tensile test is conducted and the resulting tensile strength and maximum load are analyzed. The grips are made from precisely machined, high strength tool steel.

The tensile strength of wood can be readily determined using these specially designed grips. They are designed to provide an accurate and easy-to-use method for assessing tensile strength perpendicular to the grain on different types of timber. The grips meet international standard ASTM D 143.
The grips consist of two steel specimen holders. The upper holder is attached to the load cell of the test system via a flexible coupling to provide optimum alignment. The lower holder mounts directly to the test machine base adaptor. The prepared specimen is simply inserted from the front into the holders which are designed to apply the test load to the specimen through its shoulders.

The force required to break the specimen is applied by moving the crosshead in the tensile direction.

  

ASTM D143 - 14: Standard Test Methods for Small Clear Specimens of Timber.