A single tightening of one fastener by a nutrunner or controlled power tool, logged by the controller with peak torque, final angle and a pass or fail result. Engineers read rundown curves to see thread engagement, the snug point, the torque rate and signs of cross-threading or missing parts. Rundown speed matters: running fast into a hard joint overshoots the target torque.
Pull the rundown traces for station four, every reject has the same spike, I think a cage nut is cross-threading.
Also heard as
- run down
- tightening cycle
Related terms
Nut runner
A powered tightening spindle, handheld or fixtured, that drives nuts and bolts to a controlled torque or angle.
Hard joint
A bolted joint that goes from snug to final torque in very little rotation, typically under about 30 degrees.
Rehit
Running a power tool on a fastener that is already tight, giving a false good reading or extra torque.
Breakaway torque
The torque needed to start a tightened fastener turning again, used to audit joints and rate locking features.