This is a spring-loaded head that you can attach to your CNC machine in order to mark a part with sharpie. This device can hold both Fine tip and Ultra Fine tip sharpies as there are 3 tightening bolts to align whichever pen you'd like.

Hardware required:

Qty 3: 10x32 2" long partially threaded bolts. McMaster-Carr PN: 92196A279

Qty 3: 10x32 5/16" long threaded bolts. McMaster-Carr PN: 92196A266

Qty 3: Springs 1" long. McMaster-Carr PN: 9434K44

Recommended Print notes:

Infill: 50%

Walls: 3

Print parts vertical as shown in the second picture, such that the red box is the print bed.

Print has pretty tight tolerances so may require a bit of post processing to work exactly as you intended.

Enjoy!