CNC Router Spring Loaded Pen Holder

Printed in PETG-CF 0.2mm layers, 50% infill and 4 walls. 

Pause at layer 104, carefully remove the spring cap, and insert the spring and spring cap into part A. After, continue printing to capture the spring inside the print. 

Works perfectly with a McMaster-Carr 9657K273 spring and UMR-87 Uniball refill cartridge. 

I used a little bit of PTFE lubricant on the spring/plunger as well as the cylindrical area where the pen travels to make it travel smoothly.