M2.5 Precision Hobby Knife - Upcycled Razor Blade Cutter

🪒 This ergonomic handle system allows you to upcycle standard safety razor blades for delicate cutting tasks, 3D print cleanup, and model making. Locked securely with M2.5 screws and nuts, it provides absolute stability, maximum safety, and zero blade wobble.

The project includes two distinct versions depending on your needs, and both include their respective safety caps:

• Standard Version (2 Large Fragments): Uses half of a classic razor blade. Ideal for general crafting and longer cutting edges. Uses 2 screws and 2 nuts.

• Ultra-Precision Version (4 Small Fragments): Uses a quarter of a blade (cutting the half into another half). Perfect for hyper-detailed, micro-cutting tasks. Uses 1 screw and 1 nut.

🛠 Hardware Required

• Screws: M2.5 x 6mm

• Nuts: M2.5 standard hex nuts (the handles feature dedicated slots to friction-fit the nuts).

• Blades: Standard classic double-edge razor blades.

📐 Print Settings & Orientation

To achieve the best mechanical strength and finish, the parts should be printed lying flat on the side opposite to the blade slot.

• Supports: Yes (Only small, light supports are needed under the overhanging areas due to the print orientation).

• Material: PLA, PETG, or ABS/ASA.

• Layer Height: 0.15mm - 0.20mm (lower layer height helps with tighter tolerances for the nut slots).

• Infill: 25% - 40% (Gyroid or Grid for a solid mechanical structure).

• Perimeters (Walls): 3 or 4.

💡 Assembly Instructions

1. Preparing the blade fragments:

• Half Blade (Standard Version): Carefully bend the classic razor blade in half along its long axis until it snaps.

• Quarter Blade (Ultra-Precision Version): Take one of the halves and carefully snap it in half again to get two smaller quarters.

• ⚠ Always wear safety glasses and thick gloves when snapping or handling blades!

2. Mounting:

1. Insert the M2.5 hex nuts into their respective printed slots on the handle.

2. Place the blade fragment into the designated alignment pins/slot.

3. Place the top clamp/cover over it.

4. Secure and lock the assembly tightly using the M2.5 x 6mm screws from the opposite side. Double-check that the blade does not wobble before use.

5. Slide the safety cap on when the knife is not in use.

⚠ DISCLAIMER / WARNING: Razor blades are extremely sharp. Handle them with absolute care. Always wear hand and eye protection when breaking or installing blades. Use this tool at your own risk. Keep out of reach of children. Always store it with the printed safety cap on.