This is my take on Ed Barclay's marble roller from the September 2004 issue of Canadian MeccaNotes. It's not quite complete, and it was very camera shy before I spent a day tweaking it, but it was complete enough to test and show.

The biggest departure from the original design was in the mechanism. The rack segments defeated me. When I'd get the teeth on all three segments lined up so that the spur gear would roll past them, one or more of the segments would be so much off centre that they would bind against the spur gear when everything was assembled. I ended up replacing the rack segments and the spur gears with plastic triflat gears; a 57 tooth spur gear and a 19 tooth pinion. That gave me the same 3:1 ratio that the 38 tooth spur gear and rack segment had. I didn't feel too bad about filing 14 teeth off of the plastic 57 tooth gear, though I suppose I am a Meccano mutilator now!

For some reason that I don't understand yet, my new arrangement doesn't seem to have the same "umph" as the original design apparently had. I had a lot of trouble with the second drive band slipping. Even when I fixed that by adding an idler pulley to lengthen the band, there still wasn't enough power to drive the marble feeder at the bottom of the model. So I left it out and kept the number of marbles down to 4. I haven't given up on getting that working, but at the moment I am puzzled about what to do next.

I know that I've bought a fair amount of Meccano from Ed over the years. I wonder how much of it made it into this model? I'd like to think there's a fair bit in here. It just seems right somehow!