Page 170 - Machinery Component Maintenance

152 Machinery Component Maintenance and Repair
Torquing Procedure

“Snug-up” bolts with a small hand wrench using a crisscross pattern.
Apply load evenly to all bolts. Check that the gasket is properly cen-
tered and there is a minimum of one thread extending beyond the nut
on either side.
Set the torque wrench at the initial torque per Table 4-2 or 4-3 and
apply the torque wrench in the crisscross pattern until all bolts have

Table 4-2
Torque Values (Foot-Pounds) to Achieve 50,000 PSI Bolt Stress with
Lubricated Bolts, Nuts, and Bearing Surfaces.

Final Torque
Bolt Initial Intermediate Torque Tension
Diameter (In.) Torque Torque ft-lbs Ibs

112 30 40 50 7,000
51, 50 70 100 11,000

3/4 70 100 150 17,500
718 100 170 250 24,200
1 150 250 350 31,800

1 ‘18 200 350 500 41,500
1 250 500 700 52,500

1 318 400 700 1 ,000 64,700
1 ‘I2 500 800 1,300 78,300

1 51, 800 1,400 2,100 93,500
1 314 900 1,700 2,600 109,200

1 718 1 ,Ooo 2,200 3,600 126,500
2 1,200 2,500 4,000 145,400
2 ‘14 1,500 3,000 5,800 186,900

* Based upon USA B 16.5 1968 & API Std. 60 Mar 1970