Why my ETC Auto-shutoff tool stops at lower torque than stated?

The ETC auto-shutoff (Electronic Torque Control) torque values are measured based on tuned lab conditions of regular test bolts on a hard joint, and motor powered by preset electric parameters:

  • Voltage (V)
  • Current (A)
  • Speed (RPM)
  • Timing (T)

For more information about ETC, click here

ETC tuned lab condition

However, the measured torque from this same preset parameters on tool could vary due to different joint condition below

  • Less than ideal Joint / thread condition (friction)
  • Tool and Joint alignment (angle)
  • Bolt types (e.g. Nyloc or other high friction bolt/nut)
  • Soft Joint (material deformation)

These conditions will consume extra power from motor to overcome higher friction, heat and material deformation and results lower measured torque on the joint.

For precise tightening, transducerized tool and/or torque wrench should be considered for final check.  Depending on the torque reading, double hit at the same ETC stage may be desirable for certain applications to ensure snug tight.

ETC less than ideal condition