Hi, Seems I didn't cc list in last mail with careless.
Now the latest one is: http://downloads.qi-hardware.com/hardware/milkymist_one/pcb/r4/051512/MILKYMISTONE.pdf http://downloads.qi-hardware.com/hardware/milkymist_one/pcb/r4/051512/m1r4_j27_final_keep-out.png now J27: 7 mm for copper in diameter plus extra 1 mm for keep-out layer/ring. The routes under J27 you see are in inner layer, so hexagonal spacer touches 7 mm of copper on PCB. Also for else four mounting holes now are also used by this new footprint. - adam On Tue, May 15, 2012 at 11:40 AM, Adam Wang <[email protected]> wrote: > On Tue, May 15, 2012 at 12:15 AM, Werner Almesberger < > [email protected]> wrote: > >> answering on the list, so that you don't have to search the >> backlog: >> > > sweet ! thanks. :) > > A more precise calculation would go like this: >> >> Screw head diameter 5.5 >> + head diameter tolerance 0.1 >> - chamfer at screw edge 0.1 >> + hole diameter 3.7 >> + hole enlargement due to wear 0 >> + drill position tolerance 0.1 >> + drill diameter tolerance 0 >> - thread diameter 2.9 >> + thread diameter tolerance 0.1 >> + layer registration tolerance 0.1 >> + copper width tolerance 0 >> --- >> Min. ring/keep0out diameter 6.6 >> === >> >> All distances are in mm. The numbers are measured on M1rc3, from >> the rc3 Gerbers, or simply guesses. Here is a drawing with the >> main parameters: >> >> http://downloads.qi-hardware.com/people/werner/m1/tmp/mount-dim.png > > > Nice ! This was really analyzed and discovered with cautiousness. > After discussions in #milkymist, the new size for all 5 mechanical holes > now is 8 mm in total: > > 7 mm for copper in diameter plus extra 1 mm for keep-out layer/ring. > > > http://downloads.qi-hardware.com/people/adam/m1/tmp/m1r4/m1r4_j27_keepout_layer.png > > >> "Placement (TP32, TP38-TP41) at the bottom of PCB." >> >> If we don't really care where they go anyway, then perhaps we >> should not mention their location in the schematics. >> > > removed this sentence in KiCad version. :-) > will remove it also in AD version. > > thanks, > - adam >
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