Re: Primary construction

To: tesla-at-pupman-dot-com
Subject: Re: Primary construction
From: Don Allen <dona-at-amigo-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Mon, 09 Aug 1999 17:00:12 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

At 10:42 PM 08/08/1999 -0600, Tesla List wrote:
>Original Poster: Erthwin-at-aol-dot-com 

Daniel, All,

>I just went out and bought 100feet of 1/4" copper tubing for my primary, my 
>TC is run off of a 7.5/30 NST and I have 4 strings of 10 capacitors at 0.05uF 
>1kv each (that gives a final rating of 20kv -at- 0.01uF), I'll be using a 6" 
>secondary ~25"-30" length so to achieve resonance I'll need something in the 
>area of 14 turns in my primary (given a spacing of 1/8" between each turn) I 
>was looking into possible frames to put the primary on and realized I might 
>have a slight problem. I don't have a drill press or a table saw, anything I 
>build is done with a hand held drill and a circular saw so obviously it's 
>going to be rather hard for me to get the holes drilled with anything near 
>precision and then trying to cut along the holes would be next to impossible 
>to do without ruining the entire structure, any suggestions or alternate 
>ideas?

At 1/8" between turns, it may be a llittle difficult to get a tap on the 
primary plus you could run into problems with turn-to-turn arcing. 

If it were me, I'd go 1/4" OD.

Home Depot offers pre-cut and ready-made 30" table-tops,
for the primary frame. You _could_ use a hacksaw to cut off
the tops of the primary supports (wood, HDPE) but that will
be a tedious job. A small jig-saw is well worth an investment
and they don't cost all that much nowadays. I could *not* have
finished my primary without using a jig-saw, either on the table
or the actual supports. I have a circular saw, but this isn't the
appropriate use of it on the table or the supports. I got a small
vise from a hardware store, clamped each support in the vise
and cut off the tops with the jig-saw. If funds aren't available
for a jig-saw, try asking around to see if you can borrow one.

Before I got the drill press, I used an awl punch to get the exact
center of each hole on the primary supports. That made it easy
to center the 1/4" drill bit and get nice clean precise holes in
HDPE plastic minus any of the flaking I had with drilling wood. 

I am definately a convert to HDPE over wood. :-)

Go visit http://www.fwpd-dot-net/dona/tesla/teslacoil.htm and
see "Building the Primary" page. 

Don

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"Resistance to tyrants is obedience to God" - Thomas Jefferson