Bolt Torque Chart and Preload Calculation Guide

A torque wrench measures effort. It does not measure clamp force.
Most bolted joints that leak, loosen or crack were tightened to a number. The number came from a chart, and the chart assumed a lubrication state, a thread condition and a grade that the joint on the bench did not have. Change the friction and the same torque can leave a bolt badly under-loaded or close to yield.

Most fastener references stop at a table. Engineering texts go deep on theory but leave the technician without a procedure. Bolt Torque Chart and Preload Calculation Guide joins the two: the tables you need on the job, the variables that decide whether a table value is safe, and the field procedures that make the result repeatable.

Inside, you will find:

• Metric and inch (SAE) torque and preload tables for common property classes and grades, in dry, oiled and moly conditions
• Preload and torque calculations worked step by step in SI and US customary units, from the short-form T = K x D x F to the long-form equation
• K-factor and friction references that show how much clamp force lubrication, coatings and thread condition really change
• Methods beyond torque: torque-to-angle, turn-of-nut, torque-to-yield, hydraulic tensioning and stretch measurement
• Tightening sequences and patterns for multi-bolt joints, flanges and gasketed connections
• Failure analysis and troubleshooting for loosening, relaxation, fatigue, galling, stripping and leaks
• Field-ready tools: worksheets, a torque wrench calibration log, quick-reference cards, unit conversions and a glossary