Re: More rotary gap questions..

Subject:  Re: More rotary gap questions...
  Date:  Tue, 22 Apr 1997 12:50:04 -0400
  From:  "Daryl P. Dacko" <mycrump-at-cris-dot-com>
    To:  Tesla List <tesla-at-pupman-dot-com>

At 11:27 PM 4/21/97 -0500, you wrote:

>> Now I'm wondering about the rotating electrodes, I've heard mentioned
>> brass pins, brass screws with stainless acorn nuts, and some sort of
>> threaded holder with tungsten rods.


>I can supply you with matched .250" dia. solid tungsten studs ground to
>1.5" length within .002" for $7.00 each. I use, and recommend, nothing
>but solid tungsten studs on any of the gaps that I use because of the
>durability and safety factor. Screw in inserts can work loose because
>the two different materials involved expand at different rates when
>I have 6 continuous hours of run time at 8 to 10 KW on the .250 dia.
>studs in the rotor on the series rotary gap I use with my magnifier and
>the stud erosion is minimal. In addition, when the studs do errode
>sufficiently all you have to do is pull them out and face them off on a
>belt sander or grinder and it only costs you the time it takes to do it.
>No extra cost to replace inserts!
>Safe Coiling Always,
>Ed Wingate

Thanks for the info !

I'd considered using Tungsten studs, but I'm still trying to figure out
how to hold the studs to the rotor.

I thought of drilling out a 1/4" hole in some stainless bolts and then
useing a setscrew through the side to hold the stud in place. 

But I worry about the balance of the rotor, 'tho I could machine them
till they weigh the same. The other big problem is whether the setscrews
will hold well enough in something as hard as Tungsten. I also worry
haveing so much weight at the edge of the disk

The ideal situation would be something like a collet, which would hold
the stud in place by compression, while makeing sure they were

Alas, if I had enough equipment to make such a holder, I wouldn't have
enough money to make a coil !

The hardest part of all this, is finding out what is 'good enough'.
('Tho the same can be said for most enginering...)