6.3 Grips—The testing machine shall be equipped with FIG. grips that tighten automatically and exert a uniform pressureacross the gripping surfaces. Grips shall provide adequate pressure as tension increases to prevent specimen slippage. Constant pressure pneumatic grips are satisfactory for most specimens. Test pieces shall be inserted in the grips symmetrically positioned and in axial alignment with the direction of pull. The depth of insertion of the test piece in the grips must be consistent and sufficient to prevent slipping. Type T and Type CP specimens shall be inserted in the grips as shown in Fig. 2.