Installation and Torque

With respect to installation and torque, there are three important design calculations and they are as follows:

  1. Percent Squeeze – giving standard torque installation (see Table)
  2. Compression/Stretch percent
  3. Groove Volume

Since there are wide ranges of sealing applications, more calculations may be required. If you are using standard sealing applications, then the calculations have already been done: (See tables 2 & 3) On the other hand, if the application is unique, then these calculations will need to be tabulated. IMPORTANT: Calculations must be as accurate as possible to avoid an end result of leakage.

NOMINAL SCREW SIZE INSTALLATION TORQUE (in. – lbs.)
(#4) 112 – 40 UNC – 2A 5
(#6) 138 – 32 UNC – 2A 9
(#8) 164 – 32 UNC – 2A 20
(#10) 190 – 32 UNF – 2A 23
(#10) 190 – 24 UNC – 2A 23
(#1/4) 250 – 20 UNC – 2A 75
(#5/16) 312 – 18 UNC – 2A 142
(#3/8) 375 – 16 UNC – 2A 263

Please note that the above values are recommended average values only. Variations in local conditions and the material may require significant deviations from these recommended values.