Metric Fastener Torque Guide: Why One Torque Value Is Not Enough
Torque is commonly used as an indirect way to create preload, but one torque number is not correct for every fastener of the same diameter. Thread friction, under-head friction, lubrication, coating, material, property class, joint stiffness and tool accuracy all change the torque-to-preload relationship.
Hex Bolts Guide: Sizes, Materials, Threads & Selection
Hex bolts are among the most familiar mechanical fasteners because the external hex head is easy to grip with a spanner or socket. They are used in machinery, brackets, frames.