This is a project that I had wanted to build for a long, long time, and finally tackled. This is the first project that I built on my new 14” Grizzly Band Saw. It’s all made from wood from my scrap pile, and it took about 2 days to complete. The wood used is poplar and white pine. I did not find any plans close to what I had in mind, so I literally made it up as I went. The top is a trough that is slanted away from the opening to the run. I intended to make it so small and larger marbles can fit, but when it was all assembled, the larger marbles would not fit through the last hole. The wife requested that I not fix it and just run the smaller marbles, so it will remain with small marbles. I drilled the holes using a 1-1/2” forstner bit. The channels that the marbles roll on were actually poplar turning blanks that I picked up for another project that never materialized, so I was happy to find them a home for this project. I hogged out the channels using a 1/2” straight router bit, and rounded with a 1/4” round over bit. I had seen Matthias Wandel and Norm Abrams do this on a table saw, and that was just not something I was comfortable trying out (either method). I’m happy with how the router worked out for accomplishing the channels. For the angles, I mapped out in an hour or so that the distances between the “close in” channels is 2.5”, and 9” for the wider angle. I truthfully have no idea what the actual angle is, but I decided to use Norm Abrams 4 degree angles for the angles, and while this was not accurate, it was close enough for this to work.
This was also my first attempt at a half-lap joint, which I cut out with a router (which I likely will not do this method again, it was inconsistent in depth) and trued up the cuts with the band saw. That was used on the bottom at the base (see pic). The box at the end was also my first attempt at making 45 degree cuts widths the band saw, and not surprisingly my miter gauge was a little off, but I made it work.
The first run of the marbles caused some of the marbles to jump the track, as the coves I cut out are only about 3/8” or so deep, so I milled out a 1.5”x 1/4” poplar to the sides closest to the support post to help keep the marbles in, and its a little unsightly but it works well. The decorative circles are ply, that covered an error I made when routing the coves out. It contrast well with the heat tinted poplar.
The final sanding was 220 grit on the random orbital sander. Assembly was glue and brad nails on my cheap Harbor Freight nail gun, so there are gouges all over from nailing, but it is a toy. The poplar was heat tinted, and I discovered that if you just put the pieces on the rack without a cookie sheet, they will in fact burn. Lessons learned, and I left that in there, it somewhat aged the wood in appearance. This actually doesn’t weigh much, less than 5 lbs, so it is portable despite the large size! This is pretty tall, I never took final measurements, but I hope that my kids like it. It has a satin polyurethane finish. This was a fun project!