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Project VDG machine

 

This was given to me by a retired physics teacher.? It's a Science First product and may look here a little bigger than it is.? It's 20 inches top to bottom; top terminal 8 inch diameter at the widest point; and only about 8 1/2 inches from the lower edge of terminal to the upper surface of the plastic base.? It's certainly not a beanpole which is nice, but it should be able to make a spark as long as 8 1/2 inches.

The top terminal is really appealing because my prized Harold Strand 5 inch diameter terminal machine??


produces about 12 inch monster sparks, and this SF one is quite considerably bigger at 8 inches.

When received the belt was in awful shape:? really gummy and gooey to the touch.? This gum residue was even coating both pulleys.? Cleaning off the belt and pulleys did not get a trace of voltage out of this poor thing.? That was back in humid weather so maybe now it might at least have a feeble response, although I tried the hot air trick on it to counter the humidity.

I didn't go any further then to fabricate a brand new belt, but I guess now is a good time.

There are certain things about this model that I think mechanically could be done better. It appears as if it has a bit of the flavor of improvised design to it.? The top electrode does not seem to have been manufactured for the exact purpose of being coupled with its plastic belt column.? Looks to me like it's meant to be fitted to a larger diameter column.? ?The top and bottom halves of the sphere, despite being made with a very nice stepped diameter joint, are permanently joined together. :(

Hank
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Both these pictures are from the internet.


Inline image



Inline image
Steven Greenfield AE7HD
 

I have that one from a thrift store. It was missing the support and brush assembly in the top, so I fabricated one. It works fine. I assumed the sloppy top was due to my slapdash support/brush replacement.

Later, I bought another Science First VDG on Amazon. The belt kept running off one end of the roller, and the top doesn't seem to fit well. I tried the extra belt in the box, still ran to one side of the roller. Returned it and got another, the bearing in the top was so stiff that it often wouldn't turn unless I gave the wheel a push.

Returned that one and got another. The third one works well enough to keep.

Steve Greenfield AE7HD
 

You found a Van de Graaff generator at a thrift store?? I've seen some others pretty amazing Synthesizer finds and even retro computer finds ( unfortunately, I never seem to get that lucky ), but this might be a first.? Some people have all the luck!

I got mine as a kit from Edmunds about what seems like a 1000 years ago now, well maybe only 30 or so .. but ...

- Derrik

On 11/11/19 8:41 AM, Steven Greenfield AE7HD via Groups.Io wrote:
I have that one from a thrift store. It was missing the support and brush assembly in the top, so I fabricated one. It works fine. I assumed the sloppy top was due to my slapdash support/brush replacement.

Later, I bought another Science First VDG on Amazon. The belt kept running off one end of the roller, and the top doesn't seem to fit well. I tried the extra belt in the box, still ran to one side of the roller. Returned it and got another, the bearing in the top was so stiff that it often wouldn't turn unless I gave the wheel a push.

Returned that one and got another. The third one works well enough to keep.

Steve Greenfield AE7HD
--


Derrik Walker v2.0
dwalker@...


"Those UNIX guys, they think weird!" -- John C. Dvorak
 

Thanks Hank for migrating this group to groups.io I bet that was a lot of work!

The top terminal is really appealing because my prized Harold Strand 5 inch diameter terminal machine??
?
?
produces about 12 inch monster sparks, and this SF one is quite considerably bigger at 8 inches.
A 12 inch spark from 5 inch diameter VDG is amazing, when I first saw that photo I thought it was fake!?
By Harold Strand machine do you mean that it was originally built and owned by Harold P. Strand ? If so, how on Earth did you get it ?
 

Russ,

You're welcome.? The work hasn't ended because the photos and files are lacking the contributors' names and dates of submission for one thing.?

Another effort is the old message base which was always planned to be the last component to appear.? There is recent activity that promises to provide a method to effect a good recreation of the message base.

The high performing VDG with capacitor was first published in the February 1958 Science and Mechanics by the master himself, Harold P. Strand.? The Craft Print Project (almost the same as the article) is available at the website:



The pictures I posted do have a bit of a fake look to them, but you can see that similar thick sparks of that great length are in the pictures for the article.??

In another post I'll tell about making a series of real nice and proper pictures that are unobtainium at the moment.? That picture (one is a blowup of the other) was taken by an onlooker when I did a demonstration before a small club (not of VDG people).

Hank
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On Wednesday, November 20, 2019, 05:20:58 PM EST, russ edmonds <russ.edmonds@...> wrote:

Thanks Hank for migrating this group to groups.io I bet that was a lot of work!

The top terminal is really appealing because my prized Harold Strand 5 inch diameter terminal machine??
?
?
produces about 12 inch monster sparks, and this SF one is quite considerably bigger at 8 inches.

A 12 inch spark from 5 inch diameter VDG is amazing, when I first saw that photo I thought it was fake!?

By Harold Strand machine do you mean that it was originally built and owned by Harold P. Strand ? If so, how on Earth did you get it ?
_

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