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Winding jigs: How I built mine

Hi Dave, all

Your winding jig sounds neat. Here is how I built mine:

My problem was the 8" coil former wouldnīt fit on my lathe, because it was too
long (1.10m). My lathe can only take a maximum of 10" diameter and about 33"
length.
I also didnīt want to get my lathe all messed up with epoxy or paint. So, I
needed to build a winding jig anyway and if the wire gets tangled up somehow
(winding it on a lathe) it is guaranteed to rip apart (slowest speed on mine
is 60 rpm), simply because you wonīt be able to stop it fast enough if you
(like I did) work alone. My winding fixture starts to slip at about 8-10 lbs
pull. The build up didnīt cost me a single buck because I had all the parts
and it only about 2 1/2 hrs time to finish. I didnīt go as far as Terry did
with his computer controlled winder, tho. I might wind another coil someday,
but I sure donīt plan on winding hundreds of coils (which is also the reason
why I used "wooden bearings"), but it IS a neat idea.

As I am sort of lazy, I built the jig with a motor (from an old photocopier)
controlled by a footswitch and relay. The motor already has an internal gear
box. Power (and second gear ratio) is transmitted via a small timing belt to a
sprocket from an old RC model helicopter. It takes about 3.5-4 seconds for a
full turn (i.e about 15 rpm)  This should be fast enough to get going and
still slow enough to prevent wire foul up should it somehow become tangled or
slip in between already wound wire, etc. Reversal was also possible via a
switch (although I didnīt need it)

On the end of my coil form I taped a small magnet. The winding jig has a reed
switch near the magnet. I wanted to debounce the reed switch via a 74LSxx
chip. As it turned out I didnīt need it. Two 1N4148 diodes (in series)
paralled to the reed switch reduced internal arcing to zero. The reed switch
controlles a small electromechanical counter (from the same photocopier).This
way I donīt have to count the turns and can concentrate on getting the wire
straight and tight.

The friction brake for my 22kg wire spool was simply two pieces of sponge
rubber, which were held with C-clamps.The coil form was mounted on the
threaded rod in the manner I decribed earlier in the post to Bart. 

I, too, used this jig for painting, winding, 2 epoxy coatings and a last
painting of the finished coil. The only thing that got slightly warm was the
motor. But you could still easily touch it after 5 to 6 hrs run time (waiting
for the paint or resin to harden).

Coiler greets from germany,
Reinhard


 
 Original Poster: David Sharpe <sccr4us-at-erols-dot-com> 
 
 Terry, Reinhard, ALL
 
 I've been using a winding jig consisting of a 12VDC windshield wiper
 motor powered at 18V through a 60V -at- 75A Power FET PWM'd by a 555.
 I've wound coils up to 24"OD and 3 feet long with no overloading.
 The windshield wiper motor drives a 3/8" all-thread shaft supported
 at both ends by 3/8" bulkhead bearing assemblies.  The "tailstock"
 bearing end is moveable on a wooden track and locked down with bolt and
 wingnut.
 
 The coils have a fiberglass top and bottom assembled with a 3/8"
 tapped hole concentric with coilform.  Thread shaft up coil with
 VSD portable drill, and lock at both ends with 3/8 nuts.  I place
 a spring loaded wire carrier 15'+ behind winder, and manually control
 wire feed using leather gloves (protect those fingers!!!).  A slight
 negative rake (5-10 degrees) will allow perfect close winding.  The
 motor comes with two speeds (low / fast), I wired a DPDT switch to allow
 for motor reversal, and PWM allows speed from 0.5% (motor squeals, but
 does not rotate), to 100% (about 2 turns/sec) in "high gear".  I
 included a turn counter triggered by a through beam photoeye to a 12VDC
 mechanical counter with reset.
 
 I can easily wind a 800 turn coil in less than 10 minutes, not including
 coil setup time which is required anyway. The FET's are fused at 10A
 against motor lockup, and have successfully blown without destroying the
 FET's.  Total cost out of pocket <$50 and about 3 weeks to wire and
 assemble; and worth every dime.  I have run circuit 3 days non stop
 while curing polyurtheane on coil form, and the motor was the only
 component showing evidence of heating.  Windshield wiper motors are
 cheap (less than <$20) in most locations, and are very powerful for
 their size.  I have schematic around here somewhere, may draw up in
 Excel and have available if interested.
 
 Regards
 
 DAVE SHARPE, TCBOR