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Summary:

Every week, I’m spending some time at Noisebridge and making something. This week, I spent 4.5 hours designing a replacement cap for my water bottle. Next time, I’ll attempt to 3D print it.

All of Noisebridge's equipment is donated, including its 3D printers. It doesn't have the latest Replicator, but it does stock a vintage MakerBot Thing-O-Matic and RepRap. Photo by Signe Brewster
photo: Signe Brewster

Classical music is playing. A breeze is blowing into the room, but it still smells faintly of garbage. I’m inside Noisebridge, the anarchist hackerspace in San Francisco’s Mission district, and I’m sitting at the head hacker table.

A photo from my visit to Noisebridge in August.

A photo of the table from my visit to Noisebridge in August.

Unlike everyone else at the table, I’m not creating an app or reinventing the browser or whatever else hackers do. I’m staring at a broken water bottle cap in my hand and mulling over how to turn it into a virtual 3D object on my computer screen.

Bottle cap to 3D print

After a few initial experiments, I’ve decided to teach myself how to use a 3D printer. I’m going to be spending a half a day a week over the next several weeks at Noisebridge finding out how easy it is to use modern technology (or the slightly less than modern donated technology at Noisebridge) to become a maker.

One of the greatest promises of 3D printing technology is that we might be able to revolutionize the concept of the supply chain by printing the products or spare parts we need in our homes. The plastic cap is something I really need to replace, and it’s a perfect example of what you can print with a 3D printer. But first I have to figure out how.

The bottle cap would be a great candidate for a 3D scanner, which would automatically turn it into a digital file. But I don’t have access to one and I want to make major modifications to the original design. I decide to design the cap in Autodesk 123D Design, a free, relatively intuitive design program that I tinkered with when I used a 3D printer at TechShop in July.

Here’s how my afternoon unfolded:

1 p.m.: OK, I borrowed a tape measure and recorded the cap’s dimensions. The next step is to make a cylinder to form the central part of the cap.

123D Design bottle cap

1:15 p.m.: 123D has a stock cylinder shape, so it was as easy as dropping that in and scaling it. Done. Now to make the spiral thread wrapped around the cylinder, which allows the cap to screw into the bottle.

2 p.m.: Hmm, this is harder than I thought. There’s no existing spiral shape that I can drop in and wrap around the cylinder. I can’t see any tools that indicate I could draw on a spiral in any way. To the internet!

2:30 p.m.: That wasn’t helpful. What if I use a stock shape in 123D that already has a spiral? Maybe this design for a screw will work. If I cut the top of the screw off, it would leave me with the two 360 degree turns of threads that I need.

123D Design bottle cap

3:30 p.m.: This is frustrating. The method you would use to cut through a square or other basic shape doesn’t work on the screw. I play around with some very non-traditional ways to remove part of an object and am able to remove the top third of the screw, but the rest refuses to disappear.

Screen Shot 2013-09-13 at 9.12.19 AM

4:30 p.m.: I retry a way to remove the rest of the screw, and suddenly it worked. I would not be able to replicate it, but I’ll take it. I now have exactly the height of the screw that replicates my cap. Now I’ll add a top and a loop to attach a carabiner.

Screen Shot 2013-09-13 at 9.12.41 AM

5 p.m.: Wow, that was much easier. 123D had a stock cylinder shape, which I shortened and dropped on top of the screw to create the lid. Then I used a stock doughnut shape and lowered it 50 percent into the cap, leaving a C-shaped ring. But not so fast. That lid is hanging pretty far off of the cylinder underneath it. I’m going to be working with an older 3D printer that can’t print plastic in thin air like that. A search online tells me I should taper the lip upward at a small angle, which will give the 3D printer enough support to keep printing upward.

Screen Shot 2013-09-13 at 9.13.09 AM

5:30 p.m.: Done.

That was harder than expected. While creating and sizing basic shapes like cylinders was really easy, the spiral was a huge time delay. I still haven’t learned how to create one on my own. But I’ll get better as I spend more time with 123D and I do now have a cap ready to 3D print. Next week, I’ll hook my computer up to a 3D printer at Noisebridge and print the file. Will it work? I have no idea.

  1. i gave up on you after i read that you used a tape measure. find some calipers or this will never work.

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    1. I am coming at this as a beginner, and did not think of those as an option. Thanks. I’ll take a look around Noisebridge and see if I can find one.

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  2. This was cool to follow, thanks for sharing.

    One word of caution, screw threads are quite complex and can be challenging to replicate, so make sure you get the pitch and angle as close as possible or you could damage the threading in your bottle. The trickiest dimension is the helix angle and that one is critical to achieving a solid seal.

    Good luck, hope you are successful.

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    1. Thanks for the feedback. I definitely didn’t realize what I was getting myself into by choosing this as a first project. I am quite worried about getting a solid seal. Cross your fingers for me.

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  3. I feel your pain, designing something that is a bit more complex than just a basic shape is quite difficult, I am also still trying to decide whether I should use Blender, FreeCAD or 123D for designing 3D models.

    It’s actually quite funny (I say funny here and mean depressing ^^) that I find your post here before I find my own Blog when I look for it’s Name!

    Same concept as your post though, a “noobs” approach to the “Maker Movement” =)
    I’ll just casually drop the link here and leave…

    http://www.making-a-maker.com

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