This guide shows the procces I used to create this simple, yet effective mine saw. This design was inspire by an individual who posted a similar build out of a cheap folding razor.
You'll need a retracting break away box cutter and a hacksaw blade. The tools you need can vary. I used a file, drill press, 1/8" bit, a vise and a hammer.

Step 1: Blade

Disassemble the box cutter and remove the blade. Use the blade to judge the length. Clamp the sawblade in the vise with the intended end flush with the vise. Tap the blade with a hammer to break it off. Rotate the blade in the vise so the back is facing up and file it down untill it fits into the box cutter. Now drill a hole at the end the teeth are pointed at. Reassemble the blade.