3D Printed Bolt Action Pen

Hello, I'm Nicholas, attending Dougherty Valley High School in San Ramon, California. I've always been a very forgetful person. When I was younger, I would lose jackets, lunchboxes, and even whole backpacks. This habit carried onto today. Almost daily I lose a pen, to the point where I have at least 3-4 spares in my pencil case at a time. "This habit is fine," I told myself, "Pens are cheap." But as time went on, the amount of money I was spending just buying pens just kept going up. So, I did a bit of research. Turns out, most of the cost of a pen, in my case, the Pilot G-2 07, is coming from the barrel. The refills are significantly cheaper. So, I decided to create a pen in Fusion 360 that I can easily 3D print over and over again to fit refills, all the while being higher quality and smoother than a normal G2 07.

The supplies needed for this pen are few:

• 3D printer
• ~10g PLA or ABS plastic
• Pilot G2 refill (all sizes work)

The inspiration for the pen I'm making comes from a long time hobby of mine, mechanical keyboards. I spent a lot of my time diving deep down that rabbit hole, to the point where I started to spend time with makers, the ones designing the keyboard. This led me to find a hobby in making, not just keyboards, but other products as well. Eventually, I stumbled upon the machined pen subreddit on Reddit. A quick look at the site will explain what I'm referring to. Beautiful, artisanally machined pens run in small batches to buy for an insanely high markup. This gave me inspiration to do what they did, but cheaper, faster, and easier.

From there I had to find a mechanism for my pen to use and take measurements of the pen cartridges. Because I know myself to be a pen clicker, I decided that now would be a great time to curb that habit. Therefore, I went with a bolt action mechanism, akin to one you would find on a sniper rifle. It also has the added benefit of being cool. From there, I used a set of calipers to take the measurements of the refill.

Here are the files that I used for the pen. I included .stl for easy printing and .f3d for if you want to make some edits to make it fit any pen refill you want.

This model is a difficult one to print, especially the barrel, as it is very long and thin. This means that it easily comes off the plate during printing. I struggled with this for quite a bit. It took up a large chunk of a weekend. You will need to print each part separately. My eventual fix was to turn on vase mode, or spiralize outside layer in Cura, as well as use a raft. This increases adhesion surface area, leading to less wobbling. You will also need to up the temp for the nozzle up quite a bit.

Thankfully, the pen has a simplistic design for easy assembly. First, put the cartridge inside the bolt action mechanism. This will help it from coming out when you're using it. Then, put in the bolt action piece. Then, put the pin in the J-slot. This locks the cartridge in. Finally, cap it off.

In this project, we made a unique pen that functions not only as a daily driver, but as a wonderful conversation starter too. I feel that this project turned out really well, and I learned a lot about market research, CAD modeling, and 3D printing along the way. I want to thank my friends at school for helping me come up with this idea and helping me along my journey, as well as the mechanical keyboard and pen community for helping me when I had a few kinks in the rope that needed fixing. If you have any problems when printing this, feel free to ask questions.