90 Degree Channel/Chamfer Cutter Double Blade Holder

This tool holds two metal blades tilted at 45 degrees horizontally (also 40 degrees towards the pull direction, for easier slicing). I made this tool to cut perfect 90-degree v-shaped channels into 3mm foamed PVC. It takes out a triangle of material, 1.5mm deep, 3mm across, great for making 90-degree heat-bends look sharp and create smaller fillets. The cut is made 25mm away from the straight edge of the tool (I use a printed spacer). To make straight cuts at full depth you need a good desk with a raised edge and some clamps, otherwise things will slip. It would probably work with other foamed/soft materials, like balsa wood. You will need:

2 pieces of a wide (20mm) utility knife (aka box-cutter). Make sure to break them off as neatly and safely as possible. 1 short piece of standard wood broom handle (21mm diameter) or similar. 6 small screws: two to hold the blades in, two to attach the handle mount, and 2 to reinforce the handle.

(The handle and its mount are OPTIONAL, you could put your fingers on the "wings", but it's very hard to cut straight at full depth without it.) (The pic that shows blades is from version 10 of 13, before I realized the only good place for the handle is right above the cut.) If you want me to customize some of the dimensions for you, message me.