Print the ball joint and add the negative volume to any object - done!
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updated January 27, 2025

Description

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Turn any 3D object into a Dummy 13 accessory in seconds, all in your slicer. Head, hands, you name it. Or you can add Dummy13 limbs to an object that serves as the torso, as we did with the LRSL logo.

The ball joint fits into the Dummy 13 sockets. You could just slap that onto any object but you'd have a hard time dealing with supports. This design lets you print the ball joint individually: it has a matching negative volume that allows the ball joint to be securely held in place with an M3x30 screw and an M3nS nut (DIN 562, those that are used in Prusa Printers: McMaster-Carr reference / Aliexpress non-affiliate example ).

The 200% and 250% scale files work with cylinder or rounded heads on an M3 screw. The 100% scale version requires an M3 screw with a rounded head, ISO7380: head diametre 5.7mm, head height 1.65mm. (McMaster-Carr reference).

Tips:

  • Avoid scaling your object after adding the negative volume (which would also scale and no longer match the ball joint).
  • In PrusaSlicer, if you first scale an object and then right-click > Add negative volume > Load… it may be that the negative volume is also scaled on import. However, if you first add it to the Gallery, this does not happen: right-click > Add negative volume > Gallery > Add.
  • The negative volume works best when either the slot for the ball joint OR the opening for the M3nS nut is horizontal.

Update 20240914: 250% version added, fixed: Z up for 200% version, added sample project.

Update 20240914 #2: 100% version added. This one required a complete redesign.

Update 20240914 #3: 100% version now contains socket adapters for cylinder head M3 screws. The negative volume is the same. This is what you'd have to add to items you want to use as hands, for instance.

Update 20240915: Added "Gridfinity 13" and “The Rock 13” to show some of the possibilities. Added the "Gridfinity 13 Display Stand Base".

Update 20240921 Added "Benchy 13" to the sample projects. (Comment January 2025: note that this is not a remix of 3DBenchy. The project contains the original, unmodified 3DBenchy geometry.)

Update: 20241012 Added Patrick Starfish / Cthulhu 13 to sample projects. This one is for 150% scale. I've uploaded beta versions of the 150% scale adapters as well.

WIP: a 150% version is still planned, as are the scaled versions of the socket joint.

Tags



Model origin

The author remixed this model.

Differences of the remix compared to the original

This design reuses the dimensions of the Dummy 13 joints and can thus replace any part of the original design with a ball joint.

FaultedLogic's banana for scale used in the sample project.

The Rock's head included for demonstration purposes. MasonCFrancis' head is a remix of a remix of https://www.printables.com/model/32751-dr-smolder-bravestone-dwayne-johnson .

 The “noncommerical” part of the model refers to the banana only, my adapters match soozafone's license of Dummy 13.

License