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Old Nov 25, 2004, 08:58 AM
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south shields. England
Joined May 2004
962 Posts
Coil Forming with old rubber winder

I had pensioned off this sad old indoor rubber model winder years ago, but it was suddenly re-born when an actuator coil maker was needed! For those you who may not know of this classic Peanut Scale flyers mechanism, the small cheapo calculator is used as a turns counter by connecting the "=" contacts on the calc's PCB to a micro or reed swich triggered from the primary shaft --- The method of setting it is to enter the gear ratio (9:1 in my case). and press the plus key to set up an addition constant. Each turn of the handle then briefly closes the contacts and advances the display.

I tend to use 0.06mm Thermal bonding adhesive enamelled wire for my coils, so required a 160C heat proof former to cook in the oven. A very simple solution was to mount a pair of redundant grub screwed slot-car alloy hubs on a long 3/32" steel shaft with a small turned alloy button for the coil centre former -- this centre button needs couple of turns of pastrycooks grease proof paper around it, or it never releases!! After winding on the desired number of turns, I just loosen the final gear's grub screw and slide the assembly with shaft out of the winder for cooking in a domestic fan oven (15 mins at 160C). A nice way to hold the wires in place during cooking is to slip little rings of silicone fuel tube over the shaft to trap them.

The counter is dead easy to make, and it's so good to be able to replicate coils quickly and easily.

Have fun

Peter
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Last edited by peter frostick; Nov 25, 2004 at 09:24 AM.
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