Features and Specifications

Dimensions: 80 x 30 in (6'8" x 2'6"), 200 x 76 cm

Scale: ~1:390,000

Projection: Mercator

Four stain colors — there are 25 of each color and no adjacent counties share the same color

All counties are labeled with their name in 3/8" vertical text

The outer banks are not shown (too thin) but all 100 counties are represented (no counties are exclusive to the banks)

The counties are cut out of 1/2" birch plywood and glued to another single piece of 1/2" plywood

The counties are spaced with a 1/8" gap

The Story

My friend does some work for ShopBot Tools in nearby Durham, NC. He recently let me borrow a HandiBot CNC tool.

One of the first things I did with it was cut out a small etching of North Carolina and its 100 counties…

My first presentable HandiBot creation.

It wasn’t long before I thought about cutting out the individual counties and piecing them together like a puzzle. The HandiBot has a 6 x 8 inch cutting area, so it seemed like if the largest counties filled that area I’d have a sizable (but manageable) map on my hands. (Full disclosure: I didn’t even calculate how big the map would be before I started making it. I just figured out how to scale the map so the HandiBot could manage even the largest county.) I did a test run of 10 counties with some thin wood…

Test run of ten counties — Wake county and its neighbors.

My next thought was that it’d be nice to label the counties. In the end I labeled them with their names, but I had also considered putting one or more of: population, year established, county seat, etc. but it would’ve been too busy, especially for the smaller counties.

For the text I used a simple online tool that lets you fill out a form to generate G-Code for any given text. I wrote a Python script to automatically fill out this form for all the text I needed. http://microtechstelladata.com/TextToNCcode.aspx

Here are some early labeled counties…

First attempt in labeling the counties.

For most counties, the text is placed at the centroid of the county. But I had to manually tweak the position for many counties. And for a few, I had to rotate the text.

After I figured out all the details, I entered full production mode to cut out all 100 counties.

Cutting out the counties used in the final map. Several sheets of 2x4' plywood were needed.

I used a 90 degree v-bit to cut the text and etch a bevel around the perimeter. Then a 1/8" ball nose bit was used to cut out the counties. I marked the HandiBot placement with pencil so I could do several cuts, change the bit, and then do the second pass.

After I finished cutting all 100 counties, there were obvious variances in the wood grain, so I ended up redoing a lot of the counties.

All of the counties have been cut, but some of them need to be re-cut because of the grain appearance.

Here’s what the map looked like after recutting many of the counties…

Ready to stain!

I was loving it already. I hated the idea of staining — so much work! But I knew it needed to be done.

I had the idea to use multiple stain colors. The four color theorem states that any 2-D plane can be colored with only four colors in such a way that no neighboring shapes share the same color. So I wrote some code to generate such a coloring for the 100 counties.

Testing the stain colors on some of the reject pieces.

The first results from the staining were very pleasing!

Wow! The four stain colors plus a raw, unstained piece.

The stained pieces looked great, but through the whole process of staining I wasn’t quite sure what to expect when assembling the entire map.

At this stage I had no idea how the colors would look once pieced together.

Once I started assembling it, I’m sure I had a giant grin on my face because it looked awesome…

The different colors come together quite nicely.

I also applied a semi-gloss clear coat, which didn’t turn out as nicely as I had hoped — I ended up with some bubbles hardening in it but they aren’t really noticeable unless you look for them.

Now I needed some way to mount this thing on the wall. I ended up doing a huge tiling job with the HandiBot… I penciled in a grid on a 4 x 8 foot piece of plywood and cutting 44 individual 6 x 8 inch tiles to create a single piece that I could glue all the counties onto…

The HandiBot can only cut a 6 x 8 inch area, but you can easily move it around to create large “tiled” cuts.

The backing board is inset by 1/4 inch so it isn’t visible in the final piece.

I stained the backing board too so the raw wood color wouldn’t show through the gaps between the counties. I also engraved some text on the back of it.

Title, creator and date.

I then learned that wood glue doesn’t work so well on stained wood. And it wasn’t really practical to clamp all of the counties. So I just sanded both sides really well and applied pressure for several seconds. It turned out fine — the glue doesn’t need to be super strong here.

Gluing in the final piece with Gorilla Wood Glue.

Luckily, the final product is big enough to be impressive but small enough that one person can move it around. I would guess it weighs around 50 pounds. Here I am holding the completed product…

It’s big… and heavy.

All in all, it took me 2–3 weeks to do this. I’m excited to work on more CNC projects!