Hardwood or plywood greater than 7" x 7"
1/2" thickness recommended
14mm marbles (eBay is a good source) -- 32 marbles are required
1/4" spiral up-cut bit
1/2" ball nose (1/4" shank)
tapeboard, small stop blocks, double sided tape
This project is small enough that a tape board can be used instead of placing the Shaper Tape on the workpiece.
Secure the workpiece to the spoil board with double stick tape. Use small stop blocks on three sides of workpiece to guarantee it cannot shift during cutting. The tape board secures the 4th side.
Starting with the 1/2" ball nose cutter, experiment with the value entered for cutter diameter (0.222" worked well) so that the marble recesses can be cut in helix mode. The tray around the outside can also be cut with the round nose cutter, again experimenting with the entered cutter width. Plan on cutting at least 1/8" (0.125") deep for all the marble recesses and two passes for the track. The overlap will be slight in the track and it will feel like a single round-bottom groove. Experiment with spindle speed and feed rate to minimize burning. Make a skim pass of 0.002" or slightly more additional depth to remove or minimize burn marks if necessary. Keep the router bit clean to minimize burning. Wood species selection also influences bit burn marks.
Use the 1/4" spiral bit to cut the board free. Use multiple passes and a clean-up pass for best results.
A small chamfer or round-over bit can be used in a handheld or table-mounted router to ease the outside edges.
Sand as needed, finish as needed. The examples shown are made from Sassafrass wood and sanded to p180 before applying multiple coats of an oil-varnish mix (Minwax Antique Oil). A light coat of paste wax can be added and buffed after finish is cured.
Game play rules are easily located with your favorite search engine.