Field Coil Winder using a Sewing Machine Motor.

[Yorkie]

Another high quality project in the making, David. Very smart idea to use a calculator as the counter and an equally clever idea to use a sewing machine motor an control as the driving force. You are definitely showing the way here. Inspiring stuff.
Tony

Thanks for your kind words Tony, but I'm not so much leading the way, as plundering everyone else's good ideas which I've shamelessly scavenged from here and there and cobbled together with what bits and pieces I had to hand. (The woodwork has more than a passing resemblance to the winder that Gary made). The only aspect that I can claim originality for is the feed wire bobbin tensioning arrangement, using two weak compression springs to stop the feed coil from 'free-wheeling' when the motor is stopped, risking unravelling more wire off the feed wire bobbin, or if the wire were to go slack, risking 'snatching' it and snapping the wire. By moving the outer cups on the springs inwards or outwards along the shaft, the tension can be made weaker or stronger. The inner cups with the large brass discs aren't fixed in any way - they are just slid along the bobbin shaft till they make contact with the feed bobbin, then the outer cups are positioned to apply the desired level on tension and the grub screw tightened on the cups.

I think that for wire much finer than this, I wouldn't mount the wire bobbin on a shaft - I'd lay the bobbin flat so that the wire comes off from the end of the bobbin, then have some sort of overhead feed arrangement through say a fine tube with very slight friction somewhere along the way - a bit like the Alabama Antique Radio Soc'y jobby. Just thinking out loud really - I can't see how - especially when the wire is on a large bobbin, that it can be pulled of the bobbin and onto a motor driven bobbin without risking breaking the wire. That said, I have on experience at all in the black arts of winding thousands of turns of fine wire onto coils or transformers.

For now, I'll be happy if I can successfully wind one field coil. (The only time I ever feel like doing anything twice is just before I've done it once!).