Linear Motor Based 3D Printer 5 - Magnetic Extruder Mount

I have wanted to change the extruder mount to a magnetic version for a while. First, when changing nozzles, this allows easier access. Second, I think I will put a laser on this machine in the future and this way, its an easy swap:

1 - pull off the magnetic extruder and place it on a magnetic parking mount.

2 - pull the magnetic laser holder of its parking mount and place it on the motor.

Finally, I change the configuration of the printer a lot to try out new things, and crashes are fairly common. Having the z axis run right into the hot bed makes me cringe. It is far better to have a break-away design.

My first consideration was a design similar to CNC touch probes, using ball bearing balls in 3 contact areas to make sure the head is neither mechanically over- nor under-constrained.

But I got lazy and decided to just modify an existing mount and see how it goes. This part here, is about half of what I wanted:

Technically, this design is over-constrained, but the print is accurate enough and the material flexible enough that the two parts register together very solidly without any problems. Here is my mod in Fusion360, after making the base fit my liner motor forcer and the attachment the Zesty Nimble:

I pressed some magnets I had left over from another project into both sides.

I am quite happy with the result. Here is a video: