Primary holder questions?

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Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi,

I got the primary finished.  It worked fine ;-))  I drilled up the 
supports with 1/4 inch holes but I elongated them 0.010 inch to 
accommodate the turn radius as Rich mentioned.

http://drsstc.com/~sisg/files/SISG-coil/PrimaryQ-02.jpg

As it turns out, milling the top 1/8 inch off the holes with the 10 
mil elongation was just perfect!  It was trivial just to mill the top 
more and more until just the right "snap" was obtained.  The Lexan is 
soft and pliable (brand new) and seemed not to be in danger of 
cracking at all.  So it was easy just to adjust the opening on the 
milling machine when it was being done.

http://drsstc.com/~sisg/files/SISG-coil/PrimaryQ-03.jpg

I did not have to make slits as Bart mentioned.  The Lexan seemed to 
like to flex as needed.

Then the tubing was bent in a spiral around a 4 inch form.  I then 
just put it on the Primary deck and snapped the tubing into place 
with just a little adjustment.  it was very simple to do and works perfectly.

http://drsstc.com/~sisg/files/SISG-coil/PrimaryQ-04.jpg

Cheers,

        Terry




> Hi,
>
> I am making a small 4 inch ID primary coil with 1/4 inch copper 
> tubing stuffed into 1/4 inch thick Lexan with 1/4 inch holes and 3/8 
> inch pitch.  The supports are little 1/4 inch thick Lexan chunks 
> that look like this:
>
> http://drsstc.com/~sisg/files/SISG-coil/PrimaryQ-01.gif
>
> I figure I will just mill off the top to get that "snap in" thing 
> ;-))  So I was wondering how much to mill off?  At 1/8 inch above 
> the center line I get, a "squeeze" of 0.2165 inch.  Easy to mill 
> that as much as I want to like 0.001 inch.  Don't want to go "too" far ;-))
>
> Any suggestions as to how far to mill the 1/4 inch holes for the 
> "snap in" are welcome ???;-))
>
>
> Since the 1/4 inch copper tube is running $1.60 per "foot" =:O  I 
> was wondering about smearing, rubbing, and generally coating it with 
> that electrical anti-oxidant grease used in big box connections 
> these days.  Normally an aluminum wire thing, but I wonder if that 
> grease, or some other, would help keep the copper all shinny over the years?
>
>
> I also note the little coil's Rac resistance is about 150 ohms as 
> actually measured in three ways now...  That is about 100 ohms less 
> than all the "programs" predicted...  Prolly a post for a different 
> subject line...  But all is "weird" in Rac land...
>
>
> Cheers,
>
>         Terry