This is a great model with a simple spindle attachment, but I wanted to attach this to my Carvera Air for pen plotting.   Simply attaching the pen to the collet is generally too long with a pen or sharpie inserted so you need something offset mounted.   This attachment leverages two 4mm screw holes I found unused on the side of the Z-axis bracket (mount at your own risk!).   This gives an offset around X = 45, Y = -20, however I needed to move my designs up to about a Y offset of +2 or I got a soft limit error (these offsets are not exact, but close enough to fill a piece of paper).  I have modeled the “Z” axis length to be as close as possible to the manual test probe (not the wired Z-probe) so all you need to do is set that at the tool with 0 spindle speed when setting the TLO. 

NOTE: This bracket should not affect X, Y or Z height at all once you unscrew the pen insert from the mounting bracket.  The first version did affect the X axis (shown in the pictures), but I have since updated that with version 2.

BOM:

2x M4 x 8mm screws

The authors original Pen holder

Rough Workflow:

1. Setup your “Pen Plotter” tool in your tool library (I used Makera CAM software).
   • Tip Diameter = .5
   • Half Angle = 0
   • Step Down = .2
   • Step Over = 0
   • Spindle Speed = 1 (In the G-Code file you can modify “S1 M3” to “S0 M3” to disable the spindle speed)
   • Feed Rate = 6000 (you can make this faster as desired)
   • Plunge Rate = 1000 (you can make this faster as desired)
2. Tape a piece of paper down to a flat smooth surface (cutter board)
3. Set the stock size to X = 280mm, Y = 215, Z = .5
4. Import your 2D drawing (svg file)
5. Setup a 2D contour path on the drawing path with an “End Depth = .1" and path set to “On Vector” (Don't forget to select the Pen Plotter tool you setup earlier).
6. Export from CAM to G-Code and import into the controller software, set to Anchor1 w/ offsets (X = 45, Y = -20).
7. Check to enable Auto Z-Probe and Scan margin.
8. Insert wired Z-probe as normal
9. When asked to switch to your Pen Plotter tool, insert the manual probe (also ensure you pen plotter is screwed in all the way and ready to go).  You can visually ensure that the bottom of the manual probe and your pen are about even.
10. Once the TLO height is set, take out the probe tool while it is moving to the starting position of the drawing.
11. It should lower down to -.1mm below the bottom of the manual probe and start the drawing path.
12. Enjoy the show!