Approximate Pressure in tons per linear foot required to make 90 degree air bend in mild steel.
Shaded figures represent ideal conditions for right angle bending; punch with radius equal to metal thickness and die opening approximately 8x the metal thickness. Resulting bend has inside radius approximately equal to metal thickness. If stock exceeds 1/2 inch in thickness it is good practice to increase dies opening to at least 10 times the metal thickness. Bending pressures required for other metals as compared to 60,000 P.S.I. tensile mild steel on chart.