Mr Clarke wrote:

I am mystified as to how they manage to put the windings on Toroids.

Interestingly enough, they use a toroid winding machine. A hoop is split
to fit through the core. The hoop is then used as a carrier to wrap the
wire around the core.

http://www.ruff-inc.com/toroid_machi...od=MINI-SIMPLE

Kevin Gallimore