I built one of the AVO Douglas inspired designs - the one described by Dave Gingery and it left a lot to be desired.
The original, now antique, coil winder was the Morris and it used gears to determine the ratio between coil rotation and wire movement. No possibility of slipping and good repeatability. Gingery's design substituted a disk and rubber driver arrangement for the gear shaft and that was its failing - next to impossible to get the same setup twice and even if you could, slippage was a problem.
Photos of my version of the Gingery winder and some resulting universal wound (but failure) coils.
How it Works (numbers are keyed to the photograph).
Place a hollow tube coil form on the threaded spindle (9) and tighten the conical mandrells to hold it in place. Put a spool of magnet wire on the wire holder (
thread the wire under the spindle, over the top of the wire guide and attach it to the coil form with a bit of tape or glue.
Turning the crank (1) revolves the drive shaft (2), which in turn drives the spindle through the rubber tire and disk mechanism (3) causing the coil form to revolve and take up the magnet wire. Disk mechanism (3) is held against the rubber tire by spring (4). Simultaneously, cam (5) causes cam follower rod (6) to oscillate back and forth. The wire guide (10) tracks the movement of the cam follower rod (6) thereby causing the wire to follow a universal winding path on the coil form.
With every revolution of the spindle (9) cam (7) trips a lever that advances the digital counter, thereby displaying the number of turns wound on the coil.