Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!

i3 Magnetic dual hotend mount

by karlzhao314, published

i3 Magnetic dual hotend mount by karlzhao314 Apr 24, 2016
0 Share
Download All Files

Thing Apps Enabled

Order This Printed View All Apps

Liked By

View All

Give a Shout Out

If you print this Thing and display it in public proudly give attribution by printing and displaying this tag.

Print Thing Tag

Thing Statistics

1503Views 266Downloads Found in 3D Printer Parts


This is a design for a dual extruder with a simple magnetic coupling, inspired by OpenCircuitDesign's Makergear M2 twin extruder. Essentially, there are 3 parts to it: a middle block to which the belt is affixed and a left and right block that carry the hotends (E3D v6s). The middle block is spaced so that it cannot attach to both the left and right blocks at once, so through some G-code manipulation it's able to detach and reattach to either block without any extra electronics. This allows for each hotend to be manipulated and compensated for separately similar to dual X carriages, which might be able to eliminate ooze and hotend leveling issues.

Visit this link for OpenCircuitDesign's original article and an explanation of the principles behind it:

Project is a work in progress: it's still missing the two parking points on either side of the X rods and no prototype has yet been printed because I'm still awaiting magnets.

I've more or less abandoned this project due to an interest in single-nozzle multi-material 3D printing instead. As it is, it should already work except for the wipers on each end, but is 100% untested and has no G-code written for it yet. This will remain for reference and possibly inspiration, and if I find a month of boredom one day I may come back and finish it.

Print Settings

Printer Brand:



Prusa i3


Doesn't Matter








Autodesk products export STLs in a strange orientation. Rotate and print as you see fit.



6x 8x10x8mm bronze bushing (LM8UU bearings were too long)
28x 4x2mm round neodymium magnets
M3 bolts and nuts

Assembly: Coming after I make my own prototype

How I Designed This

Inspired by OpenCircuitDesign's magnetic twin extruders for the Makergear M2, designed in Autodesk Fusion 360.

More from 3D Printer Parts

view more

Customization Apps

Edit, personalize, or revise this Thing

With 3D Slash, you can edit 3d models like a stonecutter. A unique interface: as fun as a building game! The perfect tool for non-designers and children to create in 3D.

App Info Launch App

Awesome design. Such a simple concept. I read through the website you linked and I'm very surprised more printers don't do this.
I was thinking about it, and I think you may be able to simplify the design a bit actually.

  1. You don't really need magnets on the ends for the parking position, because it doesnt matter too much that it is held rigid. The unused carriage can just sit there.
  2. The hotend holding carriages don't need linear bushings/bearings, because that will be handled by the moving carriage. You just need to design in some features that register the position when the carriages attach.

any news ? how did it work ?

got your magnets already?

Not yet, unfortunately. They ship from China, so it could be a couple more weeks. :(

they sure take their time huh?

I'm really curious about this. Would need to rework this for my core-xy though. Test it asap please

I'll try. Still awaiting magnets and time to design parking points.

This is for Prusa i3s only, but you're welcome to design a version for yourself :)

luckily I made my x-axis i3 compatible so it should be easy.