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I see that you wrote that the Lightbridge bearing is 0.155" thick, and the aluminium disc with circle laminated to it is 0.107” thick. But how thick is the aluminum setting circle disk itself?

What grade of aluminum did you use for the setting circle?

What size of thumb screw did you find worked well with the metal tab (bent over the edge of the bottom base melamine) thickness, to stop striping of the threads?

Do you find that there is any side to side wobble of the top and bottom melamine bases to be a problem with binding?

Any problems with the aluminum setting circle damaging or grooving the base melamine, or binding on the Lightbridge bearing?

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The aluminum disc is 0.090" as bought but actualy measures out at 0.094".

I believe the grade was 5053. Its a little softer and easier to work with, only because of the tab I had to bend. A higher grade would only be more money and a little tougher to work with.

The thumb screw I used is 1\4"x20tpi. Because of the thickness (or lack of), I JB Weld-ed a stainless steel jam-nut (they are 1\2 as thick as a normal nut) to the outside of the tab. You can see this in the picture. I still have to finish sanding it and shoot a little aluminum color paint on it.

I did take the wobble into account when designing it. By putting on the weight system and being able to perfectly balance any load, this has helped to minimize this greatly. Sunday night I put in my 4mm TMB\Burg. EP and tracked the core of M13 at 381x with ease.
No binding at all with these measurements. I originaly wanted 0.080" but that wasn't in stock. As a side note, I could have had the router table engrave the tick marks and the numbers on the plate with a 1\16th bit, but sadly didn't think of it till I was done.

Absolutly no binding on the LB's bearing. Once set, there is no movement of the setting circle for rubbing. There may be some on the bottom half of the base where the disk sets, but I de-burred it and sanded it with 600 grit wet\dry. This gave it enough stiction not to move, I really don't even need to set the 1\4x20 thumb screw. It will be a long, long time before there is any damage to worry about, and besides, a new base is probably in the works anyway.

Well, an engineer for sure, just not for NASA. Besides could you imagine what would happen if I got a hold of the Space Shuttle? You think it costs alot now...


(Here is the close up photo of the knob...which could be a little shorter now that I'm looking at it)