Umbo
Stats
- Height
- 245 mm
- Width
- 245 mm
- Depth
- 119 mm
- Filament
- 360 g PLA, excluding supports
- Nozzle
- 0.4 mm
Model files
A wolf’s-head umbo (boss) for a first-century scutum, after the Lauersfort phalerae and the Iberian El Pajarillo wolf head. Interpretive and decorative, not protective.
Parts
| File | Qty | Part |
|---|---|---|
wolf.stl | 1 | Wolf boss |
umbo_flange.stl | 1 | Curved flange with collar, bolt pockets and centering tabs |
dome_cover.stl | 4 | Front bolt covers |
rivet_cap.stl | 4 | Rear screw-head covers |
hand_hole_template.pdf | 1 | Grip-opening template (print at 100%) |
fit-tests/ has looser and tighter dome covers.
Printing
Print at 100%; scaling breaks the fit.
- Wolf: flat ring down. Support the hollow underside and the ears by hand.
- Flange: face up, supports under the curve and tabs placed by hand. Use 0.08–0.12 mm layers on the face.
- Bolt pockets: add walls or solid infill.
- Dome covers: stem down, rim supported.
- Rivet caps: open side up. Test the 4.05 mm hex pin in your screws.
Shield fit
The flange fits a 416 mm radius: a 300 mm straight edge across the shield shows a 28 mm gap at the middle. Other curves need a redesigned flange.
Hardware
Four each: 1/4-20 button-head socket screws, jam nuts, 1/4" SAE washers (front), 1/4" USS washers and split lock washers (rear). Screw tips must clear the front covers. Also: slow-cure epoxy and modelling putty.
Assembly
- Dry-fit everything before painting.
- Cut the grip opening from the template, keeping the grip bridge.
- Fit the flange’s tabs into the opening, trimming if needed.
- Drill four bolt holes clear of your hand.
- Mask the bonding surfaces, then finish the parts.
- Epoxy the wolf to the flange seat; fill the gaps with putty.
- Bolt through from behind: screw, lock washer, USS washer, shield, SAE washer, nut. Tighten snugly.
- Epoxy the nuts into their pockets, with release agent on the threads so the screws still come out.
- Glue in the dome covers and blend the seams.
- Push the rear caps over the screw heads.
Finishing
Sand with 400-grit. Apply Mr. Surfacer 500 and sand until smooth. Prime with high-build automotive primer, sand with 800-grit, and spray Krylon metallic bronze.