Specification Library

Suggested Assembly Torque Values to Produce Corresponding Bolt Loads

SizeTensile
Stress Area
AS
Square Inch
SA193 & ASTM 193 B7 Studs with
A194 2H Heavy Hex Nuts
Clamp Load
P. Lbs.
Tightening Torque
DryLubed
K= .223
Ft. Lbs.
K= .167
Ft. Lbs.
1/2 – 130.13810,3509672
9/16 – 120.17713,275139104
5/8 – 110.22016,500192143
3/4 – 100.32724,525342256
7/8 – 90.45233,900551413
1 – 80.59444,550828620
1-1/8 – 80.77658,2001217911
1-1/4 – 80.98473,80017141284
1-3/8 – 81.21591,12523281744
1-1/2 – 81.471110,32530762303
1-5/8 – 81.769132,67540063000
1-3/4 – 82.06154,50050243763
1-7/8 – 82.41180,75062984716
2 – 82.74205,50076385720
2-1/4 – 83.52264,00011,0388266
2-1/2 – 84.40330,00015,33111,481
SizeSA193 & ASTM 193 B7M Studs with
A194 2HM Heavy Hex Nuts
Clamp Load
P. Lbs.
Tightening Torque
DryLubed
K= .223
Ft. Lbs.
K= .167
Ft. Lbs.
1/2 – 137,8667355
9/16 – 1210,08910579
5/8 – 1112,540146109
3/4 – 1018,639260194
7/8 – 925,764419314
1 – 833,858629471
1-1/8 – 844,232925692
1-1/4 – 856,0881303976
1-3/8 – 869,25517701325
1-1/2 – 883,84723371750
1-5/8 – 8100,83330452280
1-3/4 – 8177,42038182860
1-7/8 – 8137,37047863584
2 – 8156,18058054347
2-1/4 – 8200,64083896282
2-1/2 – 8250,80011,6528726
SizeTensile
Stress Area
AS
Square Inch
SA320 & ASTM A320 L7 Studs with
A194 Grade 7L Heavy Hex Nuts
Clamp Load
P. Lbs.
Tightening Torque
DryLubed
K= .223
Ft. Lbs.
K= .167
Ft. Lbs.
1/2 – 130.13810,3509672
9/16 – 120.17713,275139104
5/8 – 110.22016,500192143
3/4 – 100.32724,525342256
7/8 – 90.45233,900551413
1 – 80.59444,550828620
1-1/8 – 80.77658,2001217911
1-1/4 – 80.98473,80017141284
1-3/8 – 81.21591,12523281744
1-1/2 – 81.471110,32530762303
1-5/8 – 81.769132,67540063000
1-3/4 – 82.06154,50050243763
1-7/8 – 82.41180,75062984716
2 – 82.74205,50076385720
2-1/4 – 83.52264,00011,0388266
2-1/2 – 84.40330,00015,33111,481
SizeSA320 & ASTM A320 L7M Studs with
A194 7ML Heavy Hex Nuts
Clamp Load
P. Lbs.
Tightening Torque
DryLubed
K= .223
Ft. Lbs.
K= .167
Ft. Lbs.
1/2 – 137,8667355
9/16 – 1210,08910579
5/8 – 1112,540146109
3/4 – 1018,639260194
7/8 – 925,764419314
1 – 833,858629471
1-1/8 – 844,232925692
1-1/4 – 856,0881303976
1-3/8 – 869,25517701325
1-1/2 – 883,84723371750
1-5/8 – 8100,83330452280
1-3/4 – 8177,42038182860
1-7/8 – 8137,37047863584
2 – 8156,18058054347
2-1/4 – 8200,64083896282
2-1/2 – 8250,80011,6528726

NOTES:
1. Tightening torque values from the formula T=KDP, where T = tightening torque,
lb. ft. K – torque friction coefficient, D = nominal bolt diameter, in.; and P = bolt
clamping load developed by tightening, lb.
2. Clamp load is also known as preload or initial load in tension on bolt. Clamp load
(lb.) is calculated by arbitrarily assuming useable bolt strength is 75% of bolt
proof load (PSI) times the stress area (sq. in.) of threaded section of each bolt
size. Higher or lower values of clamp load can be used depending on the
application requirements and the judgement of the designer.
3. No proof load has been established by ASTM. Value shown in table are assumed
at 95% of yield strength.