Re[2]: Micro fusor and Gamma Spectrum
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I actually have a 3.5" a 4" and a 5" full set of Hemispheres on hand. Not to mention the 10" set for fusor V. All are from Braun and co.

I am making a demo fusor and not a formal neutron producer, as I mentioned. A 6" set of conflat blanks and the 4" hemisphere set would have been gross over kill as the flanges would be way more than needed in thickness.

To mount the 1.33 flange I used no tube stub! I machined across the back of a threaded blank and raised a weld lip, the thicknes of the hemisphere wall. I next bored out the top of the hemisphere to make a snug fit with the raised lip on the back of the flange. I then milled a small flat area around the hole just bored in the hemisphere.
This allowed the flange to rest parallel to the hole and the lip on the back of the flange was slightly protruding into the hemisphere. This supplied more than enough filler for the TIG weld process.

I now had a mounted flange parallel to the equatorial zone of the hemisphere. I next mounted the welded flange and attached hemisphere in the lathe (equator out towards the tool post), and turned the rough extruded equatorial lip of the hemisphere flat and true to the plane of the flange.

This process will be repeated on the other hemisphere for the 1.33 flange view port.

The spark plug terminal is more than sufficient as voltges in excess of 10kv. The spark plug is one of those miniature small engine plugs and not a car plug. I may use an even smaller terminal here. Nothing in this area is set in stone yet.

Richard Hull


Created on Friday, April 20, 2001 2:49 PM EDT by Richard Hull