MakerBot Industries

When we set out to build MakerBot, we wanted to build a cheap, affordable 3D printer that we could build using commonly available parts and to make the rest of the parts using Digital Fabrication techniques. Since we had one laser cutter and zero MakerBots at that time, we pretty much had to make everything with the laser cutter.

One of the tricky parts to make is the idler pulley. These are pulleys that serve to tension the various belts in the system and they need to run smoothly. Buying a commercial part that does this would have been a few bucks, minimum. So, one night at around 2AM, I decided to see if it was possible to lasercut them. That presented its own unique challenge, since the pulleys needed to be flanged to keep the belt on the pulley.

After about 3-4 iterations, I came up with a design that used stacked layers of wood that you glued together to build a pulley. This was very tricky, and required assembling parts before you could even use them. Furthermore, the inner rings were very thin and broke easily. We were worried that they would not hold up to shipping, so we shipped extra parts. Also, being constrained by the thickness of the wood was a pretty tough challenge, and the pulleys sometimes come loose on the pulley. Not a big deal, but not elegant.

The whole reason I got into digital fabrication was because of the RepRap project, and the idea of a machine being able to make improved parts for itself. So, fast forward a few weeks and we now have 4 functioning MakerBots here at the lab. I sat down and decided to try and see what parts I could print, and the pulley stuck out like a sore thumb. I went through about 3 iterations before I landed on a nice design. The 608 bearing press-fits into the pulley and it rides like a dream. No gluing parts overnight, it just works.

If you have a MakerBot, you can download this design and print it out to upgrade your machine. How awesome is that?

This is certainly just the first in a string of printable parts that will make up the MakerBot design. We’ll be shipping these as part of the 2nd batch of CupCake CNC kits that will ship on May 1st. Hold onto those wooden pulleys, they’ll be relics someday. =)

I used to be someone who used imperialist machinery parts. I gave those up when I started designing the Cupcake CNC and I’ve never looked back. For working on projects, metric is so much easier. Ever try and figure out imperial bolt types? It’s not easy. With metric bolts, an M8 x30 means that the bolt threads are 8mm in diameter and the threads are 30mm long from the base of the head to the end of the bolt. Easy peasy. Another thing that basically makes the whole metric thing a shoe in? Black. The hardware comes in black.

Did I mention that they come in black? Besides the color black, it’s much easier to design in QCAD and Blender using metric measurements.

So, when you are embarking on making building your Cupcake CNC, we encourage you to make the shift to metric. Do yourself a favor and invest in a good metal ruler with millimeters on it and a pair of digital calipers that can switch to metric units.

Now, I will concede there is one good thing that imperialism is good for and that’s measuring the distance of objects from yourself by eye that are less than 100 feet away. When I was in the film industry, all the focus pullers, even the ones from metric countries, agreed that feet are a better unit for estimating short distances. So, unless you’re looking for a career where you’ll be judging how far away Keanu Reeves is from the lens of a high end camera, do yourself a favor and switch to metric. Your future projects thank you in advance.

Base 10 For The Win!!!!!