Torque Wrenches

A torque wrench applies a measured amount of turning force and tells you when you have reached it, which matters wherever a specification exists: line hardware, connectors, flange bolts, equipment covers and anything where too loose fails and too tight strips or cracks. Click-type wrenches are the workshop standard — the handle is set to the target value, and the mechanism gives an audible and felt click at that point, so the operator does not have to watch a scale while pulling. Micro-adjustable handles set the value precisely rather than to the nearest mark. Range is the thing to get right: a wrench is accurate through the middle of its range and least accurate at the extremes, so a job at 20 ft-lbs wants a wrench whose span suits it rather than the biggest one on the shelf. Inch-pound and foot-pound tools cover different ends of that spread. Insulated patterns extend torque work to energized equipment. A torque wrench is a measuring instrument as much as a tool — wind it back to its lowest setting for storage, and have it checked periodically.

Beam and dial wrenches are still the reference against which click tools get checked, since nothing in them goes out of calibration; they simply need the operator to watch the scale. Digital torque wrenches add an audible and visual alert at the target and, on the better ones, a torque-and-angle mode for fasteners specified that way. Split-beam designs avoid the wind-down-for-storage step entirely, which is worth having where a wrench is shared across a crew and nobody can be relied on to reset it. Whichever type, accuracy is a percentage of reading, so a 1/2-inch drive torque wrench at the bottom of its range is the wrong tool for a small fastener — keep a 1/4-inch or 3/8-inch inch-pound wrench for that work. Use a torque wrench to tighten only, never to break a fastener loose.