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G0RNN's toroidal coil winding helper

Original Date : 28 January 2015

This is a fantastically simple and useful tool designed and built by Chick G0RNN (SK) and described to me by Ray G1OJP (SK). Constructed entirely from tinplate from a large tin of baked beans or similar, the tool provides a third-hand making toroid coils easy to wind.

There isn’t a lot more to say, the design is pretty self-explanatory from the photographs. The only thing to consider during construction of the tool, is that cut tin-plate will have sharp edges, so should be smoothed with emery paper or similar before soldering.

A tinplate tri-wing spike made from an old bean can, soldered to the top of a bean can
A tinplate tri-wing spike made from an old bean can, soldered to the top of a bean can

A toroidal core former is put onto the spike and wire can easily be wound though the core
A toroidal core former is put onto the spike and wire can easily be wound though the core

The spike holds the toroid well and lets you easily pass the wire though. I’ve wound down to 5mm inner diameter coils with my version of this device. Another useful tip I found was to solder one end of the wire to the tinplate (just a tack joint), this helps get the first few turns though the toroid in place if the wire is very springy.