Re: EHT indicator: Prefered alternative d'Arsonval mounting tecnique:

Editor's note: The following offered with grateful acknowledgement to AAC member @shortbus.

Short explanation of the sketches -

1. since there are so many brands and sizes of meter available I didn't give real sizes, just letter values. Any other fractions added to the 'letter' are just to make it work, they could also be in similar metric values.

2. The meter is shown from a front and back view. There is a circle drawn on the back, since many of the meters I'm familiar with use that to enclose the meter movement. It should be changed if your meter is different, to match what you have.

3. In all sketches that have 4 small circles shown, those are holes to be drilled all at the same spacing and size. The size will need to be such to fit what ever hardware, screws and nuts, you chose to use. My suggestion would be the easily available 6-32 or 8-32 screws or metric equivalents. The length of the screws isn't given, but needs to be long enough to span the length of the assembled "stack up" of the parts, plus a little more. The 'little more' is to make it easier to start the final nuts in the stack up. You will need 4 screws and 8 nuts to fit them.

4. My suggestion would be to use 1/4 inch thick material or metric equivalent for both the locator and meter clamp. I would not use acrylic/plexiglas but use lexan/polycarbonate or another plastic for them. The plexi/acrylic is too brittle and tends to crack when working with it, but that is just my experience.

5. Depending on what you choose to use for the Faraday shield, it may be easier to cut the clearance for the mounting screws at a 45 degree angle instead of trying to drill holes. I didn't show it but probably should have. Some materials it would be hard to get a hole in the correct place due to the make up of it, so just cutting the corners to clear the screws should make life easier.

6. The 'stack up' is as follows - put screw through front panel screw hole, put mesh over screws, put locator on next and secure with first set of nuts, one on each screw and tighten them. Doing this will then allow the shield and locator to be trapped in place. Then insert the meter in the locator opening, then add the meter clamp. By then putting the final set of nuts on the screws and tightening them, you should have a meter located and Faraday shield held in place.





Here are the alternative ways of making the locator, Faraday shield, and clamp. They are to be used with the other drawings dimensions. They are easier to make only by the fact that the cutouts can be made without doing it all on the interior only. And the shield is cut on the corners instead of drilling mounting holes.
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