While running in or pulling out tubular at oil rigs the joints (tool joints) are tightened or loosened with the help of manual tongs or power tongs. Dies are the principal element in the manual tongs and power tongs which carry out the job of gripping the tool joints, before torque application. (Rollers or chains are also used for gripping of tubular while using pipe spinners) The dies are case hardened to the desired depth while leaving the inner portion (core) ductile. The hardened surface is highly resistant to wear and exhibits quality gripping of tool joints. The inner ductile core absorbs the shock of sudden impact and heavy torque. Teeth edges are slightly rounded off to eliminate the teeth bite on the drill pipe. The combined effect is an efficient operation in the long run.