Test-tube marble engine base — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/marble-engine-base/  (CC BY 4.0)
Basis: My geometry: holes on the pivot posts' and crank stands' foot patterns, M3 nut pockets at the nuts' exact 5.5 AF
Catalog version: 2026-10-20

Sizes: see table below
- 438 × 100 × 8 (y −60..40). Two beam-pivot-post-60 at x 0, y ±10 (M3 × 12, nuts flush with the underside) and two crank-stand-80 at x 192.72, y −13.5 and −45.2 (M3 × 10, nuts 1 above the underside).

feature  value
base  438 × 100 × 8
pivot posts  x 0, y ±10
crank stands  x 192.72

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/marble-engine-base/index.json
API: https://xemstudio.com/api/geometry?object=marble-engine-base