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Re: Primary holder questions?

Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Terry,

It looks like you are using acrylic for the supports. There isn't much give for snapping purposes like HDPE and this might affect the size of the "C" and how close you mill to the center of the hole. You may want to try one hole on a scrap piece of acrylic and experiment first.

Gerry R.

Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>


Mine measure right at 0.250 inches (yep! I got Starrett hole gauges too ;-)):


But I might need to "hammer" it a bit as needed  :o))

The blocks have full machine indexes so they can always be re-machined with say a 1/4 inch mill back and fourth as needed. But hammering is easy and more compatible with that "go fever" thing :o)) This project is already 6 months behind... Gotta launch!!



At 06:48 PM 7/3/2006, you wrote:
When I made mine I had to drill the holes over size because with a small
coil you get a small radius for the copper coil and if you think about
the tube you are going to snap in is not a 1/4 dia straight but a 1/4"
segment of a circle. I drilled mine approximately .007 oversize (size
"F" drill).
 Just another fly in the ointment for you.

        Rich from the middle of Missouri

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Monday, July 03, 2006 7:17 PM
To: tesla@xxxxxxxxxx
Subject: Primary holder questions?

Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>


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:


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...