A circular saw is a must-have tool for anyone who wants to do even basic woodworking. But getting clean, straight cuts is a skill that takes practice to develop. To automate the process in order to perform clean cuts every time with zero effort, Red Tie Projects created this self-guided circular saw.

This is exactly what it sounds like: a circular saw that moves across the table on its own. It rides on hardened steel rods, ensuring repeatable cuts. It also moves at a nice, steady pace, resulting in clean edges. A projected laser line shows the user exactly where the cut will fall on the work piece. A small control panel lets the user turn the machine on, start a cut, stop a cut, turn the laser on, and move forward/backwards.

On the mechanical side, this build is as simple as possible. The circular saw, which is just a handheld Makita corded model, mounts to a plate with four bearing blocks. Those bearings fit onto hardened steel rods running the length of the table. A spring-loading retraction mechanism pulls the power cord taut to keep it out of the way.

An Arduino Uno board controls the single stepper motor through a driver board. That stepper pulls the saw carriage back and forth with a belt. A relay module controls power to going to the saw. Limit switches let the Arduino detect when the saw reaches the ends of the rails. The laser line projection comes from a standalone off-the-shelf unit. The machine’s controls are standard arcade buttons.

While this saw is now only capable of doing one task, it can do it very well. For someone that performs similar cuts over and over again, it is a perfect tool.