Marble Run Kit

The model

The run stands on a baseplate (150 × 150 mm) with 36 pegs on a 25 mm grid. The columns (Ø 14 mm, heights 25, 50 and 75 mm plus a 12.5 mm spacer) have a socket hole at the bottom and a peg at the top and can be stacked. Channels and bowls each have a socket hole on the underside at their ends and are simply placed on the peg of a column. The result is an open framework you can rebuild at any time.

The channels have a round U profile with 19 mm inner diameter and 2.4 mm wall. There are straight channels (50 and 100 mm), a 90° curve (radius 37.5 mm), a sloped channel (150 mm long, 12.5 mm height difference), a stair piece with two steps, a funnel for dropping marbles in, a target bowl with a dip and a spiral (270°, 25 mm height difference) around a center column. The example run in the photo is about 19 cm tall and needs two baseplates.

Checked by calculation: slope of the sloped channel 4.8°, of the spiral 4.9°, of the funnel outlet channel 6.1°. The marble has 3 mm clearance in the channel, and the channel opening is 16.7 mm wide. At all joints the channel centers are at the same height. Pegs and holes have 0.25 mm clearance per side, the joining path has been checked with and without 0.15 mm offset, and the example run has no intersections.

View print notes (German)

Print notes included in German; part names are self-explanatory.