Swiss Army Pen

I'm a senior student at Seaquam Secondary School, and one of the most notorious classes for students struggling to maintain a high GPA is Physics 11. It's fine, but I'm never ready for any of the tests. The teacher thinks otherwise.

"There's a test on Friday. Please write this down."

At the teacher's request, I reach down and unzip my backpack. I pull out my binder and turn to a blank page. I then proceed to unzip another pocket and dig out my pencil case, which I also have to unzip and dig around in to finally procure a pencil. After writing down 3 words, I have to put everything back into my bag and walk to the next class, where this process repeats for the entire day.

Later in the day, I'm at the church, helping leaders with setting up for an activity. We're cutting 3-foot tall trees out of cardboard boxes, but the cardboard's double walled—why does it always have to be double walled!? I struggle with the only pair of scissors available, which is 3 inches long and horrendously dull.

I spotted an opportunity after that day. What if there was a way to pull my drafting and prototyping arsenal out of my pocket at any time I wanted? Inspired by the famous Swiss Army Knife, I invented this special pen, which is half as large as my original pencil case and does all the things that standard homework and sketching require. When I'm on the go, I can just pull it out and write down what I need on a pocket notebook or a stored scrap of paper in a container within the knife instead of digging around in a bag or using a phone (I don't own a smartphone).

There's less risk of poking myself, which often happens if I simply try to hold a bare pencil/pen in my pocket, and the body of the knife is wider, which keeps it from slipping out of my pocket. Have a problem with storing millions of pencils and somehow having all of them slip away? It sticks with the main frame, as well as all the other writing tools, so that you never lose it. The design of my Swiss Army Pen is modifiable too, and I encourage anybody trying this to design their own pocket writing arsenal, catered to their own needs.

Let's get to it!

Of course, a 3D printer is needed for this project. I also used super glue to lock everything in. Everything else I used was writing utensils. It might matter that you use the same pens and pencils as I did so they fit snugly in the Swiss Army Pen. Here's what I used:

#2 Staples Pencil

Gel Highlighter

Muji Gel Ink Cap Type Pen 0.5mm, or you can just buy a refill

Olfa LB 18mm blade

To hold on the blade, I used a #8-32 nut and screw (1/4").

I used Fusion 360 to design and render all of my parts.

Print one of each part (3 spacers). Initially while designing I had a problem where there was too much wiggle room for the parts, but then I got inspiration to design a part from Vex Robotics: spacers, which go onto axles and space out wheels and gears. I printed out 3 spacers to keep the parts tight.

After printing, I went online to check out colors that went well with my filament color (which was gray). Light green was an appealing result, so I rendered the knife and applied those colors to it to see if I liked it. After I decided on a good shade, I took some 'Sea Glass' acrylic paint and painted all of the parts, except for the frame, with two coats each. This was good enough for me; if you'd like, you could sand the parts smooth and prime them as well.

The highlighter and pen can be cut with the blade I used for the project, to 1.25" and 2.25" respectively. MAKE SURE not to cut through the gel-like substance in the gel pen, which includes the clear stuff.

Put together the knife in the order above. One reason I like applying the paint is because it increases the friction on the parts; bad if you want to do incredible tricks and impress your friends, but it's pretty useful for writing and actually using the pen. IMPORTANT: Make sure that you don't mix up the highlighter and pencil holders! The pencil one is slightly shorter and wider.

Inserting the pencil and highlighter is pretty self explanatory; just put them in the assigned holders. The SAP holds my pencil tightly, but has a loose grip on the highlighter, which I fixed by pushing it in with a little bit of force so it stuck.

To put in the pen, slide it into the pen holder and then screw on the cap.

The knife is slightly trickier: slide it in with the sharp side facing the longer end of the knife holder. Push it in until it aligns with the first hole. Then, put in the screw from the bottom and tighten the nut on the top end. If you do it correctly, it should not have any pointy areas exposed.

If you want to sketch, highlight, or write, simply flip out that tool and use it.

To use the knife, take off the nut and screw, slide the knife forwards to the second hole, and then screw it to that spot to hold it in a 'use' position.

I use the compartment I added to the SAP to hold an extra eraser; however, you may use it for a scrap of paper, paper clips or anything else. For people who focus heavily on drawing, I suggest opening the design for the frame and cutting out the compartment + highlighter holder entirely, and then design an eraser holder instead. I look forward to seeing someone attempt that!

Thank you for reading through this entire Instructable. It took a LOT of mental gymnastics to put this all together, and that's what I love about designing and engineering!

If you have the time, please vote for me in the Back to School Student Design Challenge. Every vote counts, and I'm grateful for everybody who helps me go further through doing that.

Until we meet again!

Isaac