Hand Coil Wave-Winder

[Yorkie]

Thanks for your kind comments Colin.

It's not really time wasted of course as it's fun to do these things.

I've just had a Poundland calculator to bits, sussed out the PCB pads for '=' key and soldered two wires to the PCB top operate a microswitch. I've made a brass cam to operate the switch with each rotation of the coil former. I'd ordered some 4BA brass slottted grub screws which arrived yesterday, so have tapped a hole in the cam 4BA to fit it to the shaft. It works a treat, and unlike the 'tally counter' I originally fitted, it doesn't place and resistance on the friction drive shaft. I've attached a couple of pics. I now need to decide how best to mount the calculator - probably double sided sticky pads, or maybe a custom-made clip. I'm hoping to get some brass sheet at Rufforth tomorrow to get on with the wire guide. All good clean fun!

Thanks so much for posting the pics of a genuine Morris Coil Winder Andy - what a rare find that must have been! I hadn't realised that it wound honeycomb and 'spider web' coils. The instructions make the differential gearing arrangements clear, and only solenoid coils are wound with a 1:1c ratio. I think it was probably an acquired skill using the winder - I wonder how many were sold? I think they date back to the mid 1930s. There's a very interesting and informative website by a Dutch radio amateur which outlines how to make such coil by hand on winding jigs, and the end results are very impressive: http://www.pa2mrx.nl/UK/coil%20homebrewing_uk.htm

One of the home-brew test gear projects I have in mind is a 'coil coverage meter'. Basically, if you have a tuning capacitor which goes from say 10pF - 365 pF, and want to know what coverage that would give with a particular coil, you set the tuning control on the meter to those settings, connect a coil under test, connect a signal generator and sweep it across the dial till you get a dip on the meter at resonance - first at the maximum capacity, then at the minimum, read off those frequencies on a frequency counter, and that tells you the coverage of the coil. It was in a 'Suggested Circuit' in Radio Constructor mag back in the 70s. Neat idea. Well I think so.

Thanks for your interest guys.