CLASSIFIED BY BIT SIZE
| Bit Size |
Torque Required at Operating RPM |
| 4" (102mm) Class | 500 ft. lbs. (69 KGM) |
| 5" (127mm) Class | 650 ft. lbs. (90 KGM) |
| 6" (152mm) Class | 800 ft. lbs. (111 KGM) |
| 8" (203mm) Class | 1,500 ft. lbs. (207 KGM) |
| 10" (254mm) Class | 2,000 ft. lbs. (277 KGM) |
| 12" (305mm) Class | 5,000 ft. lbs. (691 KGM) |
| 20" (508mm) Class | 8,000 ft. lbs. (1106 KGM) |
| 22" (559mm) Class | 10,000 ft. lbs. (1383 KGM) |
| 24" (610mm) Class | 12,000 ft. lbs. (1659 KGM) |
| 30" (762mm) Class | 20,000 ft. lbs. (2765 KGM) |
| 36" (914mm) Class | 28,000 ft. lbs. (3871 KGM) |
| 43" (1092mm) Class | 40,700 ft. lbs. (5629 KGM) |
| 48" (1219mm) Class | 50,688 ft. lbs. (7011 KGM) |
| 54" (1372mm) Class | 64,152 ft. lbs. (8873 KGM) |
| 60" (1524mm) Class | 79,200 ft. lbs. (10,954 KGM) |
| Note: The above figures are estimated at operating RPM. Bit sizes from 4" to 12" (102 - 305 mm) diameter may require a stall torque factor of three to four times the normal operating range. Bit sizes above 12" (305 mm) in diameter may require a stall torque factor of one and one half to two times the normal operating range. |
Remember: This table is only a guide. Torque requirements may vary according to down hole conditions.