# Flat-Pattern Checklist — Modular Pedestal Drum Stack ## DXF export conventions - **Units:** millimeters. Declare in DXF header. - **Layers:** - `CUT` — outer profile + holes. Color: black. Line: solid. - `BENDS` — bend lines. Color: red. Line: dashed. - `ETCH` — datum marks, alignment notches. Color: blue. Line: dotted. - `ANNO` — text, labels. Color: green. Excluded from CAM nesting. - **Origin:** lower-left of bounding rectangle. - **File naming:** `drawings/-flat.dxf` — exact part name from `cut-list.csv`. ## Per-part checklist ### Drum shells (drums 1-5) - [ ] Cut: outer rectangle of size from `cut-list.csv` - [ ] Cut: 12 lug-anchor holes ⌀5.5 mm at 35 mm above bottom edge, evenly spaced around the circumference (6 lug positions × 2 holes each) - [ ] Etch: bend-line for the inward bearing-edge chamfer (top edge, 1.5 mm down from top) - [ ] Etch: seam reference mark at the rolled-cylinder butt joint - [ ] Etch: drum-N label in `ANNO` ### Internal bracket (×15 instances; one flat pattern) - [ ] Cut: 60 mm × 60 mm blank - [ ] Cut: 2× M4 clearance holes on central flat, 12 mm apart, centred - [ ] Bend: 90° at 20 mm from left edge - [ ] Bend: 90° at 40 mm from left edge (same direction, forming U) - [ ] Etch: bracket label ### Counter hoops (drums 1-5) - [ ] Cut: rolled-flat blank of `circumference × 18 mm` - [ ] Cut: 6× ⌀7 mm holes for tension-rod claws, evenly spaced - [ ] Etch: butt-weld reference ### Base plate - [ ] Cut: 380 mm OD circle - [ ] Cut: centre 25.2 mm hole (pole pass-through, before socket weld) - [ ] Cut: 4× M8 tapped-hole pilot ⌀6.8 mm at 175 mm radius, 90° apart - [ ] Etch: alignment cross at centre + 4 cardinal direction marks at OD ## Nesting 5 shells + 5 counter-hoop blanks + 15 bracket blanks fit comfortably on a single 24" × 48" sheet of 1.2 mm CRS with ~30% utilization. The base plate cuts from a separate 6 mm plate. Nest the bracket blanks in the negative space between shell blanks; orient all bend lines parallel to the rolling direction of the sheet (if known) for cleaner bends. ## Tab-and-slot strategy Not used — every joint is welded. No mechanical interlocks. ## Validation before CAM - [ ] All bend allowances per `bend-table.csv` match the DXF flat dimensions (within 0.2 mm) - [ ] No closed paths missing on `CUT` layer - [ ] No `BENDS` lines extending past the part profile - [ ] Drum-5 shell blank fits the slip-roll min-radius coupon test (see `risks.md`)