Adjustable PVC Joints and Flanges - 3D Print Files

As seen in our Huggy Wuggy animatronic, we designed some adjustable 1" PVC hirth joints, flanges, and rotating joints that you can print and use for your projects.

The downloadable STL files and info are below.

Hirth (Ratchet) Joints

These fit 1" PVC and are printed in two parts. They're designed to fit a 1.5" long 1/4"-20 bolt. Recommended print settings below.

Flanges

These fit 1" PVC and are printed as a single piece. They have four 0.2" mounting holes that can be used with any standard screws or bolts that will fit. Recommended print settings below.

Rotating Joint

(Note: I ended up rebuilding this one slightly from what is seen in the video to increase strength, though I am still including the part I didn't use in case you don't want to get the extra bearing.)

This rotating joint comes in two parts: a sleeve to fit a 32mm bearing that then sits inside a 1" PVC coupler, and a second sleeve that fits a longer, narrower bearing. The narrow bearing fits inside the center of the 32mm bearing and the second sleeve. If you don't use the longer bearing, you can print out the second part and use the 3D printed insert instead but the strength is vastly reduced and this will be a relatively weak part in your joint that can cause issues if you have a heavier part being rotated. For example, Huggy's head was too heavy for the 3D printed insert so we swapped to the longer bearing instead.

(See picture!)

Recommend Hardware:

• Wide Bearing (32mm x 15mm x 9mm) -> https://amzn.to/46M3lth
• Narrow Bearing (45mm x 15mm x 8mm) -> https://amzn.to/3pCiVqG
• Bolts: 1.5" Long 1/4"-20
• Nuts: 1/4"-20
• Washers: 5/8" OD, 1/4" ID

3D Print Settings

On our printer, we can print these without supports, and using supports or not will depend on your printer's capabilities. Using supports won't hurt anything so don't worry if you want to add them, it just adds a minor step of removing them afterwards.

We printed our joints in PETG at 0.2mm and used a high infill (80%) to ensure they're good and strong. If you're not putting heavy tension on the joints you can do much lower infill. If you're printing in PLA, definitely test them first to make sure they're strong enough for your application before doing an entire build.

WHAT'S NEXT? STAY TUNED!

Next steps are to design and test some sleeves for adapting these joints to smaller sizes of PVC. Also testing ideas for a multi-axis ball joint for hips and shoulders...