Now the lizard-flooring project is completed, I am left with a CNC router at my disposal. I could either sell it on … or find other things to do with it. I just know I’ll be gutted if I sell it on, but later think up project after project that really needed access to one!

The building work on the house involved re-rendering a lot of the front – including covering over the truly ghastly house number that the previous owner fitted. As I had some A4-sheets of arylic left over from a previous project it seemed like a nice experiment to cut house numbers out of it.

I wanted to keep it simple – just the numbers cut out of acrylic, mounted to the wall. So, I produced the number “29” in various fonts to see which style my wife and I could both agree on. I wanted it to look different from the rest of the street, but not ridiculously crazy. The design needed to be thick enough that I could glue keyhole-hooks behind it, to mount it to the wall without any screwheads showing.

When we decided on a font, I exported the outline as an SVG and wrote some parser code for my G-Code generator (the software I wrote for cutting the lizards). I also added some simple shapes for the mounting hooks.

Click to see in more detail.

The image you see above is an SVG generated by the G-Code software, used primarily for debugging. The red line marks the original shape, the black lines the path of the drill, calculated to compensate for the drill width. The blue circles mark points where the drill will enter or leave the material. The gaps in between are “relief” points (like bridges) that will keep the numbers in place when cutting.

Looks simple enough, doesn’t it? Actually, that diagram represents a considerable amount of programming work! The lizards were fairly simple designs – quite long straight lines. But this project involves organic, flowing bezier curves; and calculating outlines around them is considerably more complicated!

We used a scrap piece of wood as a first test – acrylic is quite expensive, and scrap bits of wood are plentiful in dad’s garage.

And when that worked OK, we moved on to the acrylic:

Installed, it looks like this:I’m quite pleased with that. So … on to the next thing …