Saturday, June 29, 2019

3D Printable Wago 221 Lever Nut Mounting Blocks

I like to use Wago 221 lever nuts in place of screw terminals and have started replacing screw terminals in my 3D printers with them.  To that end I designed a few printable mounting blocks to hold single and multiple lever nuts.

The Wagos come in 2, 3, and 5 wire parts (221-412, 221-413, and 221-415), handle 24-12 gauge wire, handle 32A up to 450V, and have multiple safety certifications (unlike the much cheaper Chinese made knock-offs).  Full specs are available here.  When I first got them I inserted some wires and then pulled at them and was unable to pull any of the wires out. They really hang on tightly to solid and stranded wires.  All the wires will connect together in each block.  The 5 wire blocks are great for making DC power distribution blocks in a 3D printer, as I did in UMMD.

I have printed the 2x2 and the 221-415 mounting blocks using ABS.  The other blocks are based on the same dimensions so they should work fine.  You insert the back end of the lever nut as far as it will go into the mounting block, then press down hard on the open end and it will snap into place.  They fit and hang on tightly so there's little danger of the lever nuts coming out of the blocks, and even if they do, the bare wires are entirely enclosed within the lever nuts, so nothing is going to short.

Here's the 1x5 mounting block with a 221-415 block installed.

Yes, they're pretty small.

Here's the 2x2 mounting block.  It uses 2 screws to mount on a flat surface or t-nuts to mount on t-slot.

Here are two vertical mounting blocks that hold 4 of the 221-412 lever nuts.  The one on the left has an 8 mm tang that prevents rotation in a t-slot (so you need to use bed-only support material when printing) and uses a single t-nut to hold it in place.  I used that one to make bed heater and thermistor connections in UMMD.  The one on the right is intended for mounting on a flat surface.
The CAD file is easy to edit for any combo of lever nuts you want to make.  You can DL the Fusion360 CAD file for the mounting blocks here.


  1. Thanks Mark. These are a life saver. I didn't even know about the WAGO mounts.

    1. Neither did I until a friend who was working a a model train layout showed the Wago's to me. I took inspiration from the plastic holders that Wago makes. It's actually pretty easy to design around the lever nuts to make holders in whatever configuration you may need.

  2. Great work, but I'm not able downloading the Fusion360 Cad file. The Link opne's only a Viewer :-(

    1. I have run into this numerous times- Autodesk decided to change the way file sharing works so all my Fusion file links are broken. I've updated the link to get the Fusion360 archive file. You should be able to edit the models and export stls. Try the link above again- it should work now.


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