Re: Tungsten electrodes (fwd)

To: tesla-at-pupman-dot-com
Subject: Re: Tungsten electrodes (fwd)
From: Tesla List <mod1-at-pupman-dot-com>
Date: Mon, 15 Dec 1997 11:38:03 -0700 (MST)
Approved: mod1-at-pupman-dot-com

---------- Forwarded message ----------
Date: Mon, 15 Dec 1997 11:31:34 -0700
From: Bill Lemieux <gomez-at-netherworld-dot-com>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Tungsten electrodes

D.C. Cox wrote:

> Subject:        Re: Tungsten electrodes
> to: Gary L.
> 
> We use 1/2 dia brass with "screw-in" tungsten electrodes that have a
> 3/8-16NC thread. 

One problem with using threaded inserts of course, is that the inserts
can fly out, at deadly velocity.  

I once saw a white-hot tungsten insert fly out of a rotary gap and over
the heads of a large audience, hitting the back wall of the room with
quite a bang!  It was only sheer dumb luck that the tangent at which the
insert chose to fly off at was horizontal. Had the tangent been a few
degrees lower, it would very likely have killed someone.

If you use inserts, make sure you tighten them carefully, use a high
grade of Lok-Tite on the threads, and finally, never leave your rotary
gap physically exposed!  Always put a "bullet proof" shield around it.

Another problem is that the inserts must be as carefully weight-matched
as the permanent electrodes, to maintain balance.  Personally, I prefer
to use long enough copper-tungsten electrode to accomodate erosions, and
press them into place so that it's nearly impossible for them to come
out from vibration, thermal expansion and contraction, and the like.

-Gomez

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