MSRaynsford

At the other end of the scale it turned out I had some 5mm ball bearings kicking around and some 1.5mm thick mdf so I was able to make marble machines that were half the size of the originals. These machines are teeny and cute and also very postable so they're going up in the store for sale. http://msraynsford.myshopify.com/products/miniature-laser-cut-marble-machine-kit-1

Quite a long time ago Dominic  suggested that we should make a very large marble machine on a CNC router we have access to. It never really went anywhere but the idea came up again recently and I realised I already had all the parts required. Donkey Kong's balls  are 20mm diameter, to fake 6mm mdf I just cut 2 sets of 3mm mdf and stuck them together. I've been telling people that one of the joys of CAM is that if you want a different size you just scale everything to 200% and recut it, so I did just that. This is just Marble Machine 1 scaled to 200% and then recut and it works perfectly.