# MO-240 Maggy x48 Top Plate v2 — Shapeoko machining guide

Standalone 19 mm pedestal plate for the Roland MO-240, 48 Maggy faceplates per print. Also serves as the top skin of the full torsion-box jig.

## Stock
- 19 mm (3/4") white expanded PVC (Sintra / Celtec / Komatex), cut to **478 × 608 mm** (18-13/16" × half-sheet width, ~23-15/16"). Never oversize the 478 edge (18.82" max).
- Any thickness 18.5–19.5 works; the pocket is measured from the top surface.

## Tool
- Carbide #278 — 1/4" (6.35 mm) 3-flute upcut, 18,000 rpm. All four ops use it; no tool changes.

## Setup
1. Place the plate **portrait**: 478 mm edge left-to-right along the front, 608 mm edge running back.
2. The plate corner at the **front-left** is the one that will sit at the MO-240 table origin. Mark it.
3. Zero X/Y on that corner. If you touch the cutter flank to the fences, jog **+3.175 mm in X and +3.175 mm in Y** before zeroing (half the bit diameter). Missing this leaves a 3 mm lip along the left and bottom.
4. Zero Z on the **top surface of the plate**, not the wasteboard.
5. +X runs right, +Y runs away from you. All coordinates in the files are positive.

## Operations — run in this order

| Op | File | What it does | Time |
|---|---|---|---|
| 1 | `01 Fixture spots.nc` | 48 dimples Ø6.35 × 1.5 deep at every pedestal center | 3 min |
| — | *(by hand)* | Drive flat-head screws through 6–8 dimples that sit over solid wasteboard, spread around the plate. Snug only — Sintra crushes. | |
| 2 | `02 Pocket 8mm.nc` | Pockets the field 8 mm deep in two 4 mm passes, inside-out. Leaves 48 cross pedestals at final size (58.5 mm span). Early moves look like small circles — those are the innermost rings; it's normal. | ~75 min |
| 3 | `03 Alignment holes D7.2.nc` | 6 alignment holes Ø7.2 through, helical. Screws can stay in. Cuts 0.5 mm into the wasteboard. | 2 min |
| — | *(by hand)* | **Remove every screw.** | |
| 4 | `04 Center post relief D21x8.nc` | Ø21 × 8 mm pocket at each pedestal center (clears the Maggy plate's center post). Also erases the op 1 dimples. | 8 min |

Do not re-zero between ops.

## After machining
- Vacuum the pocket. Floor should be ~11 mm thick (19 − 8).
- Check that a Maggy plate caps over a pedestal with a light slip fit and its center post clears the relief.
- On the MO-240: nylon hex-head M4 bolts in table taps (10,10), (510,10), (10,310), (510,310); the plate drops over them. Optionally leave bolts in (110,10) and (10,110) as the prototype-jig pins — the plate clears those too.

## Geometry reference (machine frame, mm from front-left corner)
- Pedestal centers: X = 46.5 + j·75.3 (j = 0…5), Y = 46.5 + i·71.3 (i = 0…7)
- Pedestal: solid cross, 58.5 span, 28.75 arm width, corner notches 14.375 square, r2.5 convex / r3.5 concave fillets (cut r3.2 by the 1/4" bit)
- Alignment holes Ø7.2: (10,10), (10,110), (10,510), (110,10), (310,10), (310,510)
- Center relief: Ø21 × 8 deep at every pedestal center
- Pocket depth 8.0, floor 11.0 on 19 mm stock
- `Maggy x48 Top Plate v2 (machine frame).dxf` carries all of the above on layers `OUTLINE_REF`, `PEDESTAL_ISLAND`, `HOLE_D7.2_THRU`, `RELIEF_D21_8DEEP`, `FIX_SPOT_REF` if you ever need to rebuild the toolpaths in Carbide Create.

## If something goes wrong
- **3 mm lip on the left/bottom edges** → zero was set a bit radius inside the corner. Plate is still usable (pins and pedestals are correct relative to each other); either run a cleanup pass along X=0 and Y=0 at the same zero, or saw 3 mm off those two edges.
- **Plates too tight on pedestals** → tell Claude the amount; op 2 island size is a single number.
- **Post bottoms out before the plate seats** → deepen op 4 (currently 8, floor-level).