Bolt Action Pen

This is a 3D-printed pen designed to resemble a firearm barrel with a 4-lug bolt-action mechanism. The movement of the bolt extends the pen tip, allowing for writing, while retracting the bolt hides the pen tip. The design mimics the operation of a real bolt-action system, making it both functional and visually appealing. Perfect for firearm enthusiasts and unique desk accessories!

The biggest concern I anticipate is the length and thickness of the pen refill. I simply went to a bookstore and bought universal refills, but I’m unsure if this size is truly universal across different countries. My refill measures 106.5mm in length, with a metal tip diameter of 2.3mm and a plastic body diameter of 3mm. I hope these sizes are available to you as well.

If not, you can calibrate the pen by adjusting the cutout in the ammo. A separate print profile is included, allowing you to customize the hole diameter and depth to fit your specific refill.

I used a spring from another pen, but it’s not a required component—the mechanism works even without it.

Assembly instructions are available in video format: