Board: 80 × 160 × 1.6 — corners R10
Mounting: 4× M3 (Ø3.2), 68 × 146.7 spacing
Shafts: Ø6 × 20 tall · 30×30 grid · cols x=25/55 · rows y=30.5+30n
Buttons: row y=147.0 · centers x=19.9 / 33.3 / 46.7 / 60.1 · pitch 13.4 · 7.3 tall
USB-C: top edge, center x=40, 3.3 tall
Under board: leads ≤2.5 — standoffs ≥2.5
Panel holes Ø7 min for shafts. Origin: board top-left corner.