BOLT TIGHTENING SEQUENCE FOR API CLAMP USING 4 BOLTS.
Note: Washers must have proper installation orientation, as shown above.
To assemble a Clamp on Hubs, follow the Clamp Installation Instructions on this web site.
Install Fluoropolymer coated bolts, nuts and spherical load bearing washers.
After all nuts have been run down by hand, start wrench tightening following the sequence of the numbers indicated (marking the number on the Clamp with a crayon aids in keeping track of the tightening process).
Because of the nature of the fit between Clamps and Hubs, a considerable number of nut turns may occur before achieving a significant percentage of recommended torque.
During all of the following steps, keep the gap between Clamp halves even on both sides, with nuts made up approximately the same amount on each end of the bolt.
- First time around just snug the nuts with a hand wrench.
- Continue tightening the nuts, closing the Clamp around the Hub evenly, until the space between the Hub neck and Clamp bore becomes nearly equal.
- Continue tightening to achieve approximately 25% recommended torque.
- Tighten another round to approximately 50% of recommended torque.
- Again to approximately 75% of recommended torque.
- Again to 100% of recommended torque.
- Repeat this process until nuts do not move under 100% recommended torque.
- If possible, re-torque after 24 hours. Most of the bolt preload loss occurs within 24 hours after first tightening.