Wooden Railroad Stuff
Out of frustration with the instability of various blocks available for elevating tracks for wooden trains for toddlers, I decided that one of my first projects with my new Carbide3D CNC mill would be to make something so stable that even a four-year-old could not knock it over accidentally.
As the idea grew, I designed the pieces to stack so that essentially three-dimensional tracks could be constructed. The pyramidal and dome tops were a final touch added for aesthetics.
Milling this presented a number of challenges. First, the size (and efficient use of time) required that rather than milling the units out of a solid block of wood, four walls and a top were milled. The four walls fit together snugly and are glued together, with the top piece then glued on as well. The dome and pyramidal tops were milled from diminishing sizes of stacked, glued plywood (think "step pyramid") to conserve stock and because my software doesn't support rest milling. G-code was generated for each piece of the plywood stack, with milling inclusion and exclusion zones defined (exclude the area previously milled, include the incremental area). Starting z coordinate was not adjusted; instead, g-code was generated as though i would be milling from the top of the top layer of stock, but was edited to start at the actual height of each succeeding layer.
In this version, the blocks are constrained to the standard height of the typical up/down-sloping track. In the next version, this constraint will be removed, and I will provide my own sloping track to allow higher clearance to accommodate extra-tall and extra-long cars that otherwise can be caught on the tops of the openings in the walls, particularly when entering from or exiting to a sloped piece.
I also plan to add flat track sections longer than the current standard maximum length of about 11-12 inches--perhaps 18 or 24 inches. This will allow the space between relatively distant towers to be spanned without additional supports.