Many Lucas machines are equipped with Plugging Switches for rapidly stopping the Spindle Rotation. This is done for several reasons including more rapid cycling of the machine and increased personnel safety. The plugging adjustment is not particularly subject to wear and should not need periodic re-adjustment, however, in the event that your Plugging Switch needs to be re-adjusted, here is the correct process to follow:
- Select the SLOWEST Spindle Speed.
- Start and stop the Spindle Rotation several times and observe the reaction (during motor stop only) of the vertical splined drive shaft (the largest splined shaft) that carries rotational drive power to the machine headstock.
- Adjust the Plugging Switch by turning the appropriate adjustment screw in or out - as necessary - such that the splined shaft stops without coasting or 'kick-back' when the Spindle Rotation is stopped. Note that the Plugging Switch is equipped with two adjustment screws. One screw is adjusted for proper 'stopping action' from the 'Spindle Forward' (Clockwise) direction; the other screw is adjusted for proper 'stopping action' from the 'Spindle Reverse' (Counter-Clockwise) direction.
Please note that as machine Spindle speed is increased, coasting of the Splined drive shaft is normal.
