Catch-line: For those who want to build small models and need an easy and uniform way to score/cut popsicle sticks, aka craft sticks.
Summary: This is a prototype for a popsicle-sized rip saw turned on its edge which doesn't require motor or moving parts. Essentially, a razor blade is sandwiched inside a stack of popsicle sticks and clamped to a kitchen cutting board and dining room table. The stick to be cut is pushed on its edge across the horizontal surface with its face against the stack of sticks and protruding blade. Two sticks on the bottom provide spacing that will score a standard popsicle stick at about 4mm width (a popsicle stick is slightly more than 2mm thick x 9mm wide). The three sticks above the blade provide enough spacing to clamp the stack while allowing a stick to pass underneath.
Result: This was convenient for a model garage I wanted to build with a scale of 1" ~ 1mm. My ripped popsicle sticks became scaled 2 x 4 dimensional lumber which were actually 2mm x 4mm strips.
Step 1: Design Considerations
Single-stack: A single-stack setup required a minimum of four passes (once for each edge and each face) at each depth. Once scored deep enough, the 1mm wide strip could be snapped away from the finished piece(s), but not always cleanly or easily.
Double-stack (one blade): A second, opposing, stack provided adequate pressure for uniform scoring which allowed me to focus on applying even downward pressure to keep the true edge against the horizontal surface. This still required two passes (front and back) for every final strip at each depth. A minimum of two depths were needed to make clean breaks (8 passes per stick).
Double-stack (double blade): A second, opposing, blade reduced the number of passes by half. However, due to the variation in stick thickness it was difficult to find the right combination of sticks and clamp pressure to get an opposing blade lined up perfectly. This resulted in an angled final cut on many of the finished strips. Also, a fair number of strips started at the right width, but had lifted off the horizontal surface, resulting in a slightly tapered width.
Depth of Scoring: Using the double-blade setup reduced passes, but the depth of cut also played an important role. Scoring too deep made pushing the stick through the passageway very difficult, even with a follower stick to push the piece to be cut. A position where the blades almost touched worked the best without being too resistant.
Step 2: Setup Your Own Saw
- 1x pack craft sticks
- 2x C-clamp, bar clamp, or C-clamp
- 2x razor blades
- Clamp a smooth work surface (like a kitchen cutting board) to a table.
- Select two stacks of 5 craft sticks that are as close to the same thickness as possible.
- Position a stack near the edge of the cutting board and position a razor blade near the end of the stack.
- Clamp this stack loosely so the blade and alignment can be adjusted.
- Use another stick for spacing and set up a second stack loosely 1 craft stick thickness away.
- Adjust razor blades so the tips are roughly centered in the gap and as close together as possible.
- Tighten clamp directly over top of razor blades.
- Use a second clamp, if needed, to maintain pathway width at opening.
- Apply firm downward pressure on lead edge of sticks going through the pathway.
- Use a second stick to push the trail edge across the blades.
- Pull the strip through while pushing with a second stick.
Step 3: Future Design Ideas
- Place multiple blades at different depths along the scoring line.
- Try using utility knife blades. Overall they are thicker, but have a sharper point and longer tapered cutting edge.
- Design a 3D printed jig to hold the blades at various heights, kind of like: https://www.thingiverse.com/thing:2158247
- Use a machined surface and "stack" with set screws to hold the razor blade(s) in position.