CNC – Tinker and Futz

Can Your CNC Router Replace Your Planer?

The Tinkerer — Tue, 08 Apr 2014 16:47:29 +0000

When we think of CNC routers and their capabilities we often go right to the feats of complexity and precision. Impossible inlays, hundreds of exact copies of parts, complex shaping and carving, and perfect joints but not everything you use your bot for needs to be so complicated.
Flattening table tops is by far my favorite “alternate” use for my bot. I make a lot of tables and I used to haul the tabletops to a shop to have them flattened on a 4ft belt sander. They would turn out beautifully flat and smooth. On the other hand it would take time to make the trip and the shop would have at least a 2 day turnaround. There is also the risk of damaging that gorgeous glue-up in transit.

I decided to try to keep the work in my shop so I picked up a nice 2.5″ flycutter and laid a rough sawn board on the table. After a little tweaking to make the z axis perfectly perpendicular to the table, I was very happy with the results. I’ve done several tables this way. I’ve even experimented with ball-nose bits with large radius ends to create a scalloped finish.

One tip to keep in mind is to pay attention to grain direction and bit rotation. Set your stepover to a small percentage like 10% and be sure you are following the grain of the wood with your cuts. With a 10% stopover you can get very close to cutting only along the grain. Larger stopover settings will result in more cross grain cutting. This will leave swirls in your material and require you to spend a lot more time sanding.

You can accomplish this same thing with smaller bits as well. Give it shot and let me know if you have other “alternate” uses for your ShopBot.

Far Side of the Moon

The Tinkerer — Tue, 09 Jul 2013 22:23:45 +0000

“What do you want? You, you want the moon?! Just say the word and I’ll throw a lasso around it and pull it down. I’ll give you the moon, Mary. Well then, you could swallow it, and it’d all dissolve, see? And the moon beams’d shoot out of your fingers and your toes and the ends of your hair. Am I talking too much?” – Jimmy Stuart – It’s a Wonderful Life

I’ve been married to my wonderful wife for 5 years. The traditional gift for the 5 year anniversary is wood. No pressure for a woodworker… Well, she made it easy on me, she asked for the moon.

I started by consulting NASA’s website. I was in search of topographical data I could translate into toolpaths for the ShopBot. I was in luck when I found the GLD 100 map. I chose the far side of the moon since we otherwise don’t get to see it and I’ve been known to indulge in Pink Floyd.

From there my friend Ben Hribar helped me out with some photoshop work. We produced a grayscale image where lower elevations were black and the highest elevations were white. Once that was done, it was on to modeling.

The software I use with the ShopBot has a tool that allows you to import a grayscale image, set a few parameters like material thickness, the range from lowest cut to highest cut, and a few others. Once the image was processed, I was left with a 3D model ready to carve.

I created a roughing toolpath to remove the bulk of the material with a 1/2″ square endmill.

Then I created a finishing toolpath to give a nice finish with a 1/2″ ballnose mill. See my post on router bits for more explanation of these.

The moon is carved from a single piece of 3/4″ baltic birch plywood. I love the way the alternating layers of dark and light veneers accentuate the topography.

I cut a second ring to mount on the back of the moon. It’s purpose is to provide a lip to hang the moon from, hold 4 – 3/8″ dowels to bring the moon away from the wall, and to accept a strip of LED lights.

I chose analog LEDs for the price and simplicity of setting them up. The set I bought came with 16′ of LED tape, a power supply, a controller, and a remote control.

Recipe: Tool Drawer Organizer

The Tinkerer — Wed, 27 Feb 2013 17:42:27 +0000

Ingredients:

messy tool drawer
camera
CNC router
wood or foam to fit the drawer
Software to taste

Process:

Organize your tool drawer
Take picture of it
trace your tools in illustrator or any other vector based software
import your drawing into cam software
carve material using a CNC router
admire