📦 The ultimate customizable parametric box opener!
Stop ruining your keys or looking for scissors to open packages. This fully parametric OpenSCAD generator allows you to create a functional, pocket-sized box cutter tailored to your exact hand size. Designed in the style of a tactical karambit, it features a finger ring for maximum control and a mathematically generated cutting blade specifically designed to slice through packaging tape and cardboard without using metal razor blades.

⚙️ Customizer features:

• Tactical shark teeth serrations: Enable teeth_enable to generate deep, mathematically biased serrations along the blade. These aggressive teeth snag and rip through stubborn packing tape instantly.
• Ergonomic finger ring: Adjust the inner and outer diameter of the ring to fit your finger perfectly. The ring_comfort_radius dynamically generates a smooth, rounded edge on the top of the ring so it does not dig into your skin.
• Blade profiling: Fully customize the spine curvature, belly curve, and distal taper thickness. Make it a sharp, aggressive claw or a blunt safety opener for kids.
• Grip grooves: Add tactile ridges (grooves_enable) to the spine where your thumb rests, guaranteeing maximum grip and safety during cutting.

🧠 Behind the design (For makers & moderators)

Generating a clean, sharp 3D printed blade without relying on extreme boolean operations or broken meshes requires highly advanced 3D matrix math.

This model does not use standard stacked shapes. Instead, it computes an array of 6-point vertex cross-sections that sweep along a dynamically calculated spline (spine_y and edge_y). The serrations are mathematically integrated directly into the edge_y array using a phase-biased sine wave algorithm (tooth_offset). This means the serrations are not just boolean cuts, but organic curves embedded directly into the mesh structure. The result is a 100% manifold, incredibly clean polyhedron that slices flawlessly and produces a razor-sharp plastic edge right off the build plate.

🖨️ Print settings:

• Material: PLA Tough, PETG, or ABS/ASA. Standard PLA works, but PETG or PLA Tough is recommended to ensure the tip and serrations do not chip off when hitting heavy cardboard.
• Layer height: 0.12mm or 0.16mm is highly recommended! Finer layers create a much sharper and cleaner edge bevel.
• Supports: STRICTLY NONE. The model prints completely flat on its side.
• Infill: 100% solid or 40% Gyroid.
• Walls: Set wall loops to 6 to ensure the blade is entirely solid plastic, giving it maximum cutting rigidity.

❤️ Share your prints!

I love seeing your custom EDC gear and crazy blade designs. Please upload a photo of your make!

Happy printing!