Tiny Barrel Pencil Cup

Through some trial-and-error, futzing about in Tinkercad, and a lot of math, I managed to design a shape that looks reasonably close to a barrel. The staves are printed flat and then bent against each other during construction, taking advantage of the layer direction and tension and using the same engineering principles as a full-size barrel. Once constructed the entire thing holds together without any glue, and is surprisingly sturdy.

• Individual staves and hoops, just like a full-size barrel!
• Perfect for storing pencils and assorted tools!
• Assembles and holds itself together, without any glue!
• Whimsical, decorative, and almost certainly not water-tight!

Required Parts

• Staves (v2 recommended) - 24 of them, in the size of your choice. I've included files for a full set of staves attached to tabs and runners, to hold them flat during printing but also keep them all next to each other during assembly.
• Hoops - 2 sets of the 3 different sizes (6 hoops total).
• Head - Just 1 needed. It's technically optional, but adds a lot of rigidity to the finished barrel. Also prevents your pencils from falling straight through the thing when you pick it up.

Print all parts flat to the bed, no supports necessary. My examples are made with:

• Amolen walnut PLA for the barrel parts
• Overture space-grey flavored PETG for the lighter hoops
• Carbon fiber PLA for the darker hoops
• 2 walls, 0.2mm (0.3mm first) layers

When slicing the staves, having them so close to each other might “convince” your printer to ignore the gaps between them. Make sure your resolution, slicing gap, and line widths are set so that each stave is still separated in the middle. I also recommend setting your slicer's wall order to print the outer walls first.

Assembly Tips

(See photo)

1. By far, the easiest way to keep all your staves lined up is to let your printer line them up for you (I highly recommend printing the staves with runners attached, instead of individually). Once you've got them lined up, run a piece of tape down the middle to prevent them from twisting around during assembly.
2. Leaving the tabs on, bend the staves around in a circle and fasten your tape, making sure the innermost set of grooves is exposed (I had to tear away some tape to do so). Work the largest set of rings around the very top and bottom.
3. Firmly press on opposite sides of the hoops, being sure to rotate and flip often to keep them level until fully seated. Once they reach the right position, the lip on the bottom of each ring should register into the grooves on the staves (you should feel a small “click” when it's correctly seated).
4. With both large hoops nice and tight, take a deep breath and cut away the runners, then remove your tape. Everything should hold together. The tops of the staves should be close enough together to fit through the next size hoop with minimal fuss. There's nothing scientific about getting the head of the barrel to stay put; I just held it in place with my fingers until I could get the last hoop on. You might need a chopstick or some other poking apparatus to get it seated.

v2 Updates:

• Added a small bit in the center of each stave, connecting all the small “islands” down the length. This still allows for the grooves to hold the hoops in place, but makes for a much easier print.
• Decorative grooves on the barrel head have been shifted over, for the same reason.
• Bigger hoops would occasionally pop off the barrel when putting on the smallest hoop. Large and Medium hoops have been tightened slightly and the grooves “nudged” a bit outward. The result is a much better fit, and hoops falling off is no longer a problem. The tighter tolerance means it's no longer possible to print all three hoops nested inside each other, but a full set of 6 will still fit nicely on the build plate.