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Re: spark gap

One further note on reducing the field concentration at the ends of segmented
copper-pipe static gaps: use the "dullest" wheel-type pipe cutter you can find,
and dial-in a lot of feed rate during the first several turns of the cutter. If
you are using normal drawn copper tubing, this procedure will help to "pinch"
the tube at the point of the cut, increasing the gap at the ends of paralleled
tube segments. After cutting through the pipe, use 220 grit abrasive paper to
remove break the remaining sharp edges.

I have intentionally "dulled" a spare cutting wheel for this purpose by
securing
it on a machine screw with double nuts, then chucking the assembly up in a hand
drill and dressing the edge of the wheel on a sharpening stone to achieve a
small radius rather than a sharp edge.

Scott




Tesla List <tesla-at-pupman-dot-com> on 02/11/2000 10:57:13 AM

To:   tesla-at-pupman-dot-com
cc:    (bcc: Scott L Hanson)

Subject:  Re: spark gap



Original Poster: "Jim Lux" <jimlux-at-jpl.nasa.gov>

The field strength is strongest at the edge on the end.  If you carefully
round the ends in it will probably help.  I have found that if you use a
wheeled type tubing cutter, it produces a slight turn in on the edge which
works very nicely to get rid of the field concentration at the end of the
cylinder.  A bit of sandpaper to take the sharp edge off also helps.

----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: spark gap
> Date: Thursday, February 10, 2000 2:51 PM
>
> Original Poster: Parpp807-at-aol-dot-com
>
> Hi all,
> I have just completed and tested a multiple SG for my bipolar coil. I
used
> eight copper
> sweat couplings, each of 1-inch diameter and gapped at 0.022 inches. The
> problem
> is getting all these cylinders lined up and well behaved enuff so I can
gap
> them to at least within
> 5/1000 of eachother. I wonder if anyone has developed a technique for
doing
> this.
>
> When I tested the gap, I noticed that all the sparks were on the circular

> edge of each cylinder rather than along the adjacent sides where I
expected
> them to be. Isn't this where the spark should be to gain the advantage of

> cooler operation?
>
> Happy day,
> Ralph Zekelman
>
>