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Re: Primary Construction
Tesla List wrote:
>
> >From DELCOKEVIN-at-aol-dot-comThu Sep 5 22:18:02 1996
> Date: Thu, 5 Sep 1996 11:44:44 -0400
> From: DELCOKEVIN-at-aol-dot-com
> To: tesla-at-pupman-dot-com
> Subject: Primary Construction
>
> Everyone,
>
> I am getting ready to wind my primary for my latest coil.
> It will use ~12 turns of 3/4" or 1" copper tubing.
>
> I have my own ideas, but, I would like input from anyone who has built a
> similar primary
>
> as to their construction techniques.
>
> Kevin M. Conkey
Hi Kevin:
My primary uses 1/2" diameter copper tube, however some of what I did
may provide some ideas to help you with your larger diameter tubing
primary construction project. I started with the idea of a 11" I.D. and
I think it is a 40" O.D. setup with 1/2" spacing. My first step was to
create an Autocad drawing of a spiral, with a 5.5" radius that grows to
6.5" 360 degrees later. Sounds crazy, but keep reading! I screwed this
down to a 4' x 4' sheet of plywood and put two (notched to interlock at
the same plane or level) 4' long 2" x 1" boards crossing over the top of
the spiral piece. Now I wound my first turn of tube and then laid in a
piece of 1/2" rope at the "step" in my first turn spiral. Using the
rope as a spacer is an idea that was posted about 8 or 9 months ago and
it works great. Now I just kept on going turn by turn while dressing in
the rope and copper tube. Some turns I rotated the tube around the form
assembly, other "we" rotated the entire form. The "we" was me, my wife
and daughter. I could not have finished with as good a primary without
their help, if at all. I would suggest you will have accomplished alot
if you are able to wind the 3/4" or 1" alone. I would recommend getting
help!
I hope that the above description can be pictured without re-reading it
23 times. I wonder if you could find a suitable spacer? If I did it
over, I would start with about a 3/4" smaller radius because of the
spring back on the tube after releasing it. I wanted the primary to
have as uniform spacing as possible and quite simply, to look good. The
above process gave me very satisfactory results.
I used nylon 101 combs to hold up the tube. Using a mill I cut arcs
every 1" using a 1/2" mill and position it so that the centerline is
about .055" below the top edge of the nylon piece with the piece laying
on it's side. The result is that the tube will "snap" into the cuts
made in the edge of the nylon. You end up with a hole that is about 230
degrees of a full circle, with that extra little bit of material locking
in the tube. Hope that's clear.
Good Luck!
Chuck Curran