I didn't feel that this would fit anywhere but general since my MK1.5 is modded to an overhead gantry setup.
I made a pen mount that uses Cricut pens to print graphics.
My Phlatprinter uses changeable faceplates similar to the MK3.
Video is here

 

That's working pretty good. What's the fit like between the pen and the white pipe piece? Is the front screw to stop the pen from falling or adjust the fit?

 

Hey Jeff that's cool! Could you show us more details? Is there a spring inside the pipe pushing on the pen or is it just gravity?

 

Ok, I used the Cricut pens because they are round with a groove in it to use a screw to hold it in.
A piece of half inch pvc pipe fits the pens perfectly and it has a spring that I got from a spiral notebook that rests on a screw that goes straight thru the pvc pipe towards the top.
I ran around buying truck shock springs all day yesterday and either they were too big in diameter or were just too stiff.
The spiral spring from a $.49 notebook works wonders, I just cut one end off and unwound it then cut the length I needed.
Now I can change colors as needed and they will always be the right depth because of the way the Cricut pens are designed

 

they are just a marker like a sharpie