Bolt Pen - Bolt Action Pen

Clip Update Out Now!

• New deep carry pocket clip option for all models.

Features:

• Smooth and elegant bolt-action design.
• 3 models:
  • Standard: which uses a Pilot G2 or similar refill. (140mm total length)
  • Mini: which uses a Parker-style refill. (127mm total length)
  • Micro: which uses a G2 Mini refill. (110mm total length)
• Stylish spiral-shaped grip.
• Deep carry pocket clip option.
• 4 different options for how far the tip of the refill sticks out of the pen (the amount varies depending on the refill used):
  • #2: 2.5-3mm
  • #3: 3.5-4mm
  • #4: 4.5-5mm
  • #5: 5.5-6mm
• Easy to print with minimal supports needed.
• No glue required: only a refill and spring.
• Simple assembly process with minimal parts.
• All parts except for the pen body are interchangeable between models.

Filament:

I used Polymaker's Polylite Clear PETG for the pens shown. Avoid using filament with weak layer adhesion, such as matte PLA, as the pen will break after minimal use in the bolt area. I have found PETG to work well, and I believe normal PLA is fine too, although I haven't yet tested it.

Print Settings

I recommend using the .3mf file as that includes the correct print settings. Otherwise use:

• 0.15mm layer height
• 3 walls
• 0.4mm nozzle (may benefit from 0.2mm)
• Tree supports on build plate only
• Arachne wall generator
• Auto brim

Assembly:

The assembly process is identical for all models. You’ll need the correct refill for the model your using, along with a spring. You will need the correct spring for the model you're using too. If you printed one that specified a G2 spring, make sure you have a G2 spring. If not, any spring with around a 4mm diameter should work. Note that spring length affects tension; if the tension is too high, use a shorter spring or cut one down.

During assembly, you’ll also need something long and slim, like a pencil, to help align the parts.

Note that the bolt mechanism should become smoother with use.

Also note that the #5 barrel won't fit in the G2 version of the Standard and Micro models without shortening the spring. The #4 barrel should fit but only just, and if not, then you can also slightly shorten the spring.

I'd love to here from you and see your prints, so please add a make and rate my model. Thanks!

Change log:

• (11/2/25)
  • Changes to the description:
    • Added more info to the Print Settings section.
    • Added the part about the barrels to the end of the Assembly section.
  • Slight changes to the print settings in the .3mf file. 
• Clip Update (28/1/25)
  • New deep carry pocket clip option for all models.
• Micro Update (1/1/25)
  • New Micro pen size which fits a G2 mini refill.
  • Redesigned cap thread for easier, support free printing of the end cap.
  • Changes to parts of the description that were incorrect or no longer applied due to the update.
• Spring Fix V2 (16/12/24)
  • The last spring fix failed to resolve the issue where the Pilot G2 spring wouldn't fit in the pen. This should now be resolved. I have added a 3rd plate to the print profile which includes the standard sized pen, that now fits the G2 spring (plate 3). For any other spring you should still use the non-G2 spring version (plate 1). Note that the mini sized pen (plate 2) will fit any spring including the G2 spring.
• Spring Fix (20/11/24)
  • changed diameter of spring area from 4.9 mm to 5.1 mm to accommodate pilot g2 spring (Standard Pen).
  • change spring area length from 6 mm to 6.5 mm to accommodate slightly longer springs (Standard & Mini Pen).

*I released this model on MakerWorld on the 29/10/24. This is why there have been multiple documented updates to the design before I uploaded it to Printables.