# RD – Rundown

Tools
ES STR SL ST SR QST IXB

Rundown step is the part of the tightening from when the screw enters the thread until just before the screw head touches the underlying surface and snug point is reached. The torque required during rundown does not contribute to any clamping force.

This step runs the tool with the speed in the forward direction, and depending on the Rundown Type, Torque or Snug the step behavior is as follows:

Rundown Type: To Torque: The step stops when the specified target torque is found.

Rundown Type: To Snug: The snug gradient calculation starts at the specified torque trigger level Tt. If no torque trigger is set the gradient calculation is started at the start of the step.

The slope calculation is made between two angle points Ad degrees apart and is calculated as: (Tn – Tn-1) / (An – An-1) and as soon as two slopes after each other are larger than TSLOPE the snug point is found.

Parameter | Description
--- | ---
Rundown type | To Torque or To Snug.
Target torque | Default: "not set". Must be > 0.
Speed | Default: 60 rpm. Must be > 0.
Speed ramp type | Hard, soft, or manual. Default: Hard. If you select Manual, the Speed ramp field opens.
Speed ramp | If Speed ramp type is Manual, this field opens. Default: 500 rpm/s.
Trigger Torque | If Rundown type is To Snug, the Trigger torque field is displayed. Default: "not set". Must be > 0.
Delta Angle | If Rundown type is To Snug, the Delta angle field is displayed. Default: "0". Must be > 0.
Torque Rate | If Rundown type is To Snug, the Torque rate field is displayed. Default: "0". Must be > 0.
Brake (Valid only for Power Focus 6000 StepSync, Power Focus 8 StepSync, and Flex). | If On the tool will be stopped when the target is reached. If Off the program goes directly to the next step without stopping the tool.

Point and click on image to see more information:

A | Snug Point
B | Angle Delta
C | Torque Slope
D | Torque Target
E | Torque Trigger