Hey Guys,
Perhaps we need some cross sectional sketches so we are all on the same page.....
Doing a 2.5mm counterbore (recess) in a 4mm panel (so the pot grips onto the remaining 1.5mm) should be fine. even 1mm will be fine. The strength comes from the whole panel around the counterbore. Of course if you are lining up counterbores across the whole width of a panel, leaving not much meat in between, that's another matter.
For material selection, I disagree about the warping after machining. Of course the correct alloy needs to be used... the softer bendy ones that are good for folding and welding are no good for machining, so you would not use them anyway. Anodized engraving sheet comes dead flat, and i have not had a problem with any warping during machining. Most issues with the finished product not being flat is because of guillotining before it goes on the machine. Also if you are laser cutting the panel, it will probably not end up flat.
The limiting factor here is the availability of different thicknesses in the correct alloy (something like 6061T6) - and in an array of colors. I am currently working out my supply chain for this....particularly nice colors in thicker 6061, for 19" panels. I am seriously considering getting set up to do anodizing myself.
I am not 100% sure why the pot nut and washer needs to be covered by a cosmetic plate... are they not covered by the knob anyway? given we are talking about machining anyway, what does the cosmetic plate achieve that a 2mm counterbore in a 3mm plate will not achieve? Perhaps I am missing something.
Anyway, now I am rambling.
On a side note, almost bang on 4 years ago I documented the build of my second CNC machine here, but then work took over and I did not to get to do much with it since. Well that has now changed and I have finally been able to start spending some time in the workshop building. I really should revive that old thread and get some pics up.
Cheers,
Tim