Flat Spiral Construction Tips

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Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi All,

I mentioned in an earlier post (I hope it went through, haven't seen it)
that I built a flat primary. I picked up a 5 dollar roll of carpet tape.
This stuff is thin, very sticky, and double-sided. I covered a flat
former with tape. I put the former onto a round wooden table which
spins. I then simply put a screw in the middle and started winding. I
finished at 15" outer diameter. Small wire was fine with this process
(used 24awg magnet wire). Here are two photo's showing the coil half
wound and then fully wound. The little tool has a smooth curved bottom
which I used to butt the winding next to it's neighbor as it was wound.
Please read on after taking a peak at the photo's.

http://www.classictesla-dot-com/temp/Flat15-2.jpg
http://www.classictesla-dot-com/temp/Flat15.jpg

Later that night, I thought I would coat the winding. This spelled
disaster. The coating wicked between the windings and the tape lifting
the wire up and literally destroyed the coil. DOH!

So, I wound another coil since the process worked so well. This time, I
wound it on a plexisheet. This one came out "much" nicer than the first
you saw in the photos (must be all the practice). It's 14" in diameter.
Today I removed a few turns from the center which provided an inner
radius of 0.625". I put another piece of plexisheet on top of the
windings. Here's the new specs.

13.9775" outer diameter
0.625" inner diameter
298 turns (counted)
14.2 ohms (measured)
12mH (measured)

This one calc'd at 12mH by Acmi (just to note it).

No pictures yet on this one. I'll wait until I get everything finished.

Take care,
Bart