Variables Affecting the Assembly Bolt Stress Developed During Manual Tightening

This paper is concerned with an ongoing program that explores the effect of different variables on the bolt stress developed during manual bolt tightening. Research published in 1936 by Mr. E. C. Petrie[1] established an empirical relationship relating bolt diameter to the probable bolt stress resulting from the manual assembly techniques of the day. That relationship currently appears in Non-Mandatory Appendix S of Section VIII of the ASME Boiler and Pressure Vessel Code [2]. Taking the Petrie stress relationship a step further, this research examines the effect of several known, important variables on the original Petrie stress formula. This paper reports on results with lubricated and un-lubricated bolts ranging from 5/8 in. to 1 in. diameter tightened by various male and female mechanics who are experienced, or not, and trained, or not.Copyright © 2011 by ASME