My design for a clean, maintainable wiring harness

I’ve been working on tidying up my recently-built machine (, notably the wiring (and adding an air blast system), and decided that I wanted a really clean way to do the stepper wiring. To that end, I designed and printed some components.

The wiring harness bits are designed to fit inside my tubing, with just a tiny lip to stop it from going fully into the tube. They have slots that securely hold female JST SM connectors. One side has 2 connectors (one for a motor, and the other is the output to the controller) and all the wiring for the serial harness is done internally on this side. The other side is just a single connector for the other motor. The wiring slots fit 18ga wires, which is overkill but will significantly reduce voltage drop (I’ll be running 18ga back to the controller as well). The “top” and “bottom” of the design are flattened so they can be printed without supports.

In order for this design to work, I had to redesign the roller plates – the stock design blocks access to the end of the tubing, and I needed full access both to install the system at all and to be able to plug in the male connectors later.

I’m really happy with this solution. I like that it turns all the wiring into a clean, modular system. If I ever need to partially disassemble this thing for maintenance, dealing with the wiring is now super easy since it’s all just easily-accessible plugs.

My design is hard-coded for my tubing size right now (1.00" OD / 0.75" ID) but if there is enough interest I’d be willing to go back and parameterize the design and share files.


Slick design.

It looks like (but not quite sure) on the double plug it doesn’t matter which goes to the motor and which goes to the board. My brain hurts whenever I try to work out the orientations.


Neat. There used to be a part that would fit an ethernet port in the end of the tubes that was pretty popular. I like that the wiring is internal, as long as it never fails.

TBH I’m not entirely sure if it matters or not, I’ve haven’t looked at the wiring from both ways. The way it’s wired now, one plug at each end has a blue/red/green/black set intended to be the motor connections (with the wiring colors corresponding to those coming from the motors themselves), and the second plug at one end has 2 blue and 2 green connections – that one is intended to be the connector that goes to the controller. When installing them in my machine, I put the motor connection facing up and the board connection facing down as a matter of convention; if I ever forget for some reason it’s pretty easy to pull out the end piece slightly to take a look.

That looks really good. The worst part about rebuilding my XY the last time was having to resolder all the joints.