Keeps a water bowl topped up. You provide the bowl and the water bottle. You must drill out the cap. See instructions.
There are a few of these water bowl things on Thingiverse. Most of them print the bowl along with the bottle holder. I wanted one that would clip to the side of the bowl I already have. I also decided to incorporate the bottle's own cap instead of printing a thread. STEP and Fusion 360 files provided if you want to vary the dimensions.
Updated: version 2 files have a hook on the lip to stabilize from side to side nudges, if your bowl has a flange like mine. The model was also redrawn to simplify the design history and put more dimensions in parameterized sketches.
Updated: v3 cap holder has an extended back wall to provide a larger contact patch when printing in two parts. Use with the v2 tub. Single print model should not have a delamination issue.
Updated: v4 replaces the open tub with useless side vents with a solid holder with a full hole to provide more surface area for the cap to grip.
If you have a Dremel, check out my bottle cap hole drilling jig to adapt your bottle cap.
Take the water bottle cap and drill out the top. You want a big an opening as possible. My largest drill bit wasn't big enough, so I ended up filling it larger. You can tell it is big enough when water glugs out of the bottle when held upside down without jostling or squeezing.
If your bottle cap is slightly under 31mm in diameter, you can glue it into position at the outside end of the mount. I used a generous amount of two part epoxy around half the cap and part way around the top. You will want to use an adhesive that can stand up to the shear forces of opening and closing the cap.
There are three STLs provided, one which is the whole part, and two which are the bracket arm and the mount as separate parts for printing separately without support, which you can glue together using IPS Weld-On #4 (for PLA or ABS), acetone (ABS only), or superglue. Print the arm with one side down, and the mount with the bottom down.