Edge-X :A Finger-Mounted Precision Cutting Tool

Hi, I’m Arush, currently pursuing a B.Tech in Mechanical Engineering. If you’ve seen my other Instructable, you’ll know I enjoy making papercraft models with hundreds of pieces. But there was always one problem: cutting and scoring those pieces with regular paper cutters or X-Acto knives gave me hand cramps, and using them requires keeping the blade perfectly perpendicular to the surface to get a straight cut—which is hard to maintain during long sessions. Instead of struggling, I decided to invent my own tool. That’s how Edge-X : A Finger-Mounted Precision Cutting Tool, was born.

Let’s dive into my thought process and how I built it.

Exoskeleton

1. 3D Printer – to print the exoskeleton structure
2. 9 mm Paper Cutter Blades – used as the cutting blade
3. Sandpaper – for smoothing the print surface
4. Acrylic Paint – for coloring the print
5. X-Acto Knife – to cut off any connected supports
6. Pliers – to remove stubborn supports

Glove

1. Arm Sleeves – used as the base for the glove
2. Cotton Fabric – adds structure and improves the look
3. Rexine (Faux Leather) – for decoration
4. Sewing Machine – to stitch everything together
5. Aluminum Tape – for decorative accents

The two problems I wanted to fix with traditional paper cutters and X-Acto knives were:

1. Making them more comfortable to reduce hand cramps.
2. Designing a tool that doesn’t require a proper holding technique.

Let’s expand on the second problem. If you’ve ever tried cutting a thick sheet of paper or cardboard with a ruler, you’ll know that if the blade isn’t held perfectly perpendicular to the surface, it gets caught in the material and results in a curved line. Keeping the blade perpendicular at all times is very difficult, especially during long cutting sessions.

My solution was to attach the blade directly to the tip of the finger instead of mounting it in a holder like a pen. When holding a pen, your wrist has the freedom to rotate up to 90° side-to-side, which makes it harder to keep the blade straight. But when the blade is mounted on the fingertip, your wrist is naturally locked in place, and since fingers don’t rotate sideways, the blade stays almost perfectly perpendicular to the surface.

For comfort, I took inspiration from exoskeletons. They provide support to the body part they are attached to and, after some use, start to feel like an extension of your body. Similarly, with practice, this tool begins to feel like an extension of the hand.

Prototyping is key to turning an idea into a real product—it helps you figure out what works and what doesn’t before committing to the final design.

For my first prototype, I focused on getting the dimensions of my finger. I used masking tape for this: I wrapped the tape around my finger with the adhesive side facing outward so it wouldn’t stick to my skin. Once my finger was fully covered, I carefully removed the tape to get a mold of my finger. I then split the mold into two sections and taped a 9 mm blade piece to the tip.

This prototype gave me a general shape to work with and served as a template for the next stages of development.

With the second prototype, I focused more on the shape and structure of the finger cap and blade holder.

To start, I carefully cut open the first prototype, laid it lat on a piece of paper, and traced its outline. This gave me a basic template for the cutting tool. I then cut out the pieces from a 300 gsm sheet of paper and built the blade holder using masking tape and additional paper.

By the end of this stage, I had a somewhat working prototype and could start focusing more on refining the design.

For the design of my cutting tool, I took inspiration from the “Ripperdoc Gloves” from Cyberpunk 2077.

The futuristic Cyberpunk design worked perfectly with the concept of my cutting tool, as both share a similar idea: enhancing the functionality of the hand with fingertip-mounted tools.

Prototype 3

For the third prototype, I reused the same template from Prototype 2 but created a new cap for the fingertip and a redesigned blade holder. I then coated the whole structure with super glue to make it as stiff as plastic. For the adjustable strap, I used rexine and connected both parts with two strips of paper.

Next, I painted the entire prototype black and added details with aluminum tape. I also made some extra decorative pieces to place on top, imitating the hydraulic supports from the Ripperdoc Gloves.

In the end, the design theme actually came out looking more like steampunk, with its black and silver finish, rather than the futuristic Cyberpunk style I intended. However, the cutter itself worked flawlessly, proving that the concept is solid — it’s only the design aesthetics that need further refinement.

To refine the final design, I searched Pinterest for futuristic exoskeletons, gloves, tech gear, and similar tools, saving the designs that inspired me.

Next, I needed sketches of the cutting tool from different angles. To get accurate proportions, I found a 3D hand model online, took screenshots, and printed them out. This gave me a proper base to draw on without worrying about the proportions of the human hand.

Using the reference images, I selected the design elements I liked best and incorporated them into my sketches, which completed the final design concept.

To create the 3D model of the exoskeleton, I used Blender. While Blender isn’t particularly known for precision modeling, I improved its accuracy by enabling the MeasureIt add-on and setting the unit scale to millimeters.

The MeasureIt add-on allows you to take precise measurements of your parts, which was critical for designing my model accurately.

To test the dimensions, fitting, and strength of the design, I first decided to make some test prints.

For the first test print, I modeled only the blade holder and the front cap to get a baseline. I kept the design simple, exported the model as an .fbx file, and then converted it into a .3mf file.

The print came out too tight, but the height and thickness were accurate. After reviewing the model, I realized that if a part has hollow sections, the layers shrink slightly while cooling. To counter this, it is best to add about 0.5 mm to the radius.

For the second test print, I increased the inner radius by 0.5 mm and also added supports to the side of the blade holder. This time, the fitting was perfect, but the blade holder became weaker instead of stronger. Upon closer inspection of the broken piece, I noticed that it snapped along a flat surface with no reinforcement. This happened because the support structures I added were not connected to the cap. After correcting this issue, the front section of the design was successfully completed.

My design includes two movable positions with joints. To ensure that the joints could be printed as a single piece while still maintaining movement, I conducted several test prints.

I first printed the model, inspected it for errors, and then adjusted the dimensions where needed. After three iterations, I was able to achieve a fully functional joint.

With the joints working as intended, the next step is to combine everything I learned from the test prints and move on to the final print of the complete design.

I began by modeling the blade holder, reinforcing it with additional supports and incorporating the design details from my sketches. Next, I created the joint that connects the front section to the midsection of the exoskeleton.

The joint that connects the midsection to the knuckle was slightly different, since I decided to print the knuckle section separately for better accuracy. Once all components were completed, I exported the models.

Finally, I arranged all the parts on the build plate and started the final print.

The glove is a crucial part of my design because it connects the exoskeleton to my hand while also enhancing the overall look of the final product.

To create the glove, I used stretchable arm sleeves. This material allowed me to keep the design simple, as it naturally conforms to the shape of my hand. I traced my hand onto the fabric and cut out the required pieces.

Since I am not very experienced with stitching or using a sewing machine, I asked my mother for help. She handled the main stitching on the sewing machine, while I focused on adding the finishing details.

With the glove complete, the only task left was to assemble the exoskeleton and attach it securely to the glove.

The first step was to fix the mid joint, which had broken while I was removing the supports. Once repaired, I sanded and painted some sections of the cap and blade holder, and added strips of rexine to introduce texture and variation.

To enhance the appearance, I covered the joint bolts with aluminum tape, giving them the look of real metal components.

The biggest adjustment I made was to the knuckle piece. It turned out larger than expected, so I cut it down and kept only the left side, which I stitched onto the glove to secure the exoskeleton. I also stitched the bottom of the midsection directly to the glove for extra stability.

With everything assembled and connected, Edge-X was finally complete.

This was such a fun project to work on! Taking a real problem I faced and solving it with something I designed and built from scratch was an amazing experience. The final product not only looks great but also works flawlessly.

Through this project, I learned a lot about 3D printing and precision modeling—skills I’m excited to apply to future creations. And you can be sure that Edge-X will become an essential tool in my upcoming papercraft projects.

Thank you so much for taking the time to read through my project. I truly appreciate it!

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