Push Button Pen

Pen with push button mechanism. You need the insides of a normal pen (ink tube+spring), as shown in the picture. There's an option to use a 9x34 mm spring inside the pen if you want to make pressing the button a little bit stiffer.

Some tips to make the pen work smoother:
-Use fine layer height, especially with the white parts (shown in picture)-
-Sand any rough spots in the “crown” section of white parts
-Add lubricant to make operation smoother
-Pay attention to the ink tube, an edge could cause sticking when pressing the button. See details in the picture.