You can see there is a drive shaft which transmits power to the opposing chuck.
This allows for the coordinated rotation of both ends of the wire mandrel under power.

The source spool of kanthal heater core wire is mounted on a constant tension dereeler device which is mounted directly to the traverse assembly.
The source spool traverses at the same rate as the coil as it is wound.
This allows the source kanthal wire to maintain a narrow angle to the mandrel wire

The demonstration machine is configured to wind a coil as long as 24 inches. The coil length can be a long as 39 inches with an optional extended traverse housing.