Rough Fusion 360 model of a five-segment underbody skid plate set for a 2005 Jeep Grand Cherokee WH, 3.0 CRD, Quadra-Drive II. Built to establish the layout and the build script; every dimension is an estimate awaiting real measurements from the vehicle.
PROVISIONAL — not measured off a car
All station positions, widths and hole placements below were derived by the agent from published WK/WH platform figures (wheelbase 2780 mm, overall length 4740 mm) and from where components sit on that platform in general. Nothing was measured. The user will supply exact sizes; until then this model is a layout sketch in solid form, not a cut file.
Coordinate Convention
| Axis | Meaning |
|---|---|
| Y = 0 | Nose of the vehicle |
| +Y | Rearward |
| Z = 0 | Underside of the plate |
| X = 0 | Vehicle centreline (all plates centred on it) |
All five segments lie along the centreline.
Common Construction
Shared by every segment:
- 4 mm plate
- 30 mm upturned side flanges
- 11 mm bolt holes at the corners, plus a 3-across row every ~250 mm of length
Segments
| # | Covers | Y range (mm) | Length | Width (mm) | Access holes |
|---|---|---|---|---|---|
| 01 | Front radiator + steering | 350 – 900 | 550 | 720 | — |
| 02 | Engine / oil pan | 900 – 1650 | 750 | 800 | 3 x 34 mm |
| 03 | Transmission (NAG1) | 1650 – 2250 | 600 | 700 | 2 x 34 mm |
| 04 | Transfer case (NV245) | 2250 – 2800 | 550 | 640 | 2 x 34 mm |
| 05 | Fuel tank | 2950 – 3800 | 850 | 920 | 4 x 34 mm |
Segments 01–04 butt together with no gap. There is a deliberate 150 mm gap between 04 and 05 (Y 2800 → 2950) for the crossmember and exhaust routing.
The 34 mm access holes are for drain plugs and service points — again, positions are assumed, not confirmed against the actual pan/case.
Front plate (segment 01) came out at 1483 cm³.
The JEEP Cut-Through Problem
“JEEP” is cut clean through segment 01 — 180 mm cap height, centred at Y = 625.
The text is sketched on the plate’s bottom face so it reads correctly when viewed from underneath. Sketching on the XY construction plane instead gives text that reads right from the top and mirrored from below — see 9. Text meant to be read from below must be sketched on the bottom face.
The P's counter falls out
A through-cut leaves the enclosed bowl of the P as a loose island — it appears as a separate body. Fixed with two 7 mm stencil tie bars: one running left through the stem, one running up through the top of the counter. Without both, the island drops out. Full pattern in 8. Cutting text through a plate creates disconnected lumps.
Structurally, this is the wrong place for it
A 180 mm through-cut sits on the plate that takes the worst hits, and the open letterforms will pack with mud. Alternatives offered to the user, no decision made yet:
- Engrave rather than cut through — keeps full section
- Move the mark to the fuel tank plate — flatter, rearward, far less impact exposure
- Keep the cut-through and accept both downsides
Open Items
These block turning the model into anything real:
- Frame-rail bolt positions — the whole hole pattern is currently invented
- Actual width at each station — the floorpan narrows and widens; the table above assumes smooth taper
- Z step between stations — the floorpan is not flat front-to-rear, but the model treats Z = 0 as one continuous plane across all five segments. This is the biggest single inaccuracy in the model.
- Branding decision (see above)
Related
- offroad-armour
- geo-tracker-front-diff-shield — the other model from the same session
- fusion360-mcp-scripting — gotchas 5–9 came out of building this