Tunnel Portal, Single Track (O)
A single-track tunnel portal at O (1:43.5): 124.1mm wide and 151.7mm to the top of the parapet, with a 96.6mm bore springing at 69.0mm — off a 4200mm prototype bore with a 600mm arch ring. The ring comes out 13.8mm, so it is a genuine arch rather than a hint of one. Print it on its back: the bore becomes a vertical hole through a 10.3mm plate, the crown never has to be bridged, and the one feature that would otherwise force supports costs nothing. Voussoirs and brick courses are deliberately not modelled — at O they would be a fraction of a nozzle width, and a smooth face you can paint beats a mushy one you cannot.
from £25.18example, in PLA
Example pricing
A guide only — not a fixed quote. Final price depends on material, quantity, print orientation and printability.
| Material | 1 unit | 5 units | 10 units | 25 units |
|---|---|---|---|---|
| PLA | £25.19 | £105.78£21.16/unit | £191.41£19.14/unit | £428.15£17.13/unit |
| PETG | £26.45 | £111.09£22.22/unit | £201.03£20.10/unit | £449.66£17.99/unit |
| ABS / ASA | £29.20 | £122.63£24.53/unit | £221.90£22.19/unit | £496.36£19.85/unit |
Per-unit prices fall with quantity. Larger batches are cheaper still — ask for a bulk quote.