Automating Circular Saw Operation

Circular saws a very useful tools, but they can also be difficult to operate well. It is hard to get clean and straight cuts, especially the cut is long. That's why so many people own table saws, because they let you move the work piece instead of the tool. But even a table saw requires careful feeding to get good edges. It would be nice if the tool did all of that work on its own, which is exactly what Red Tie Projects achieved with their automatic circular saw project.

This is a circular saw that automatically slides across the table on rigid rails at a smooth rate. It ensures that every cut is perfect, because it will be absolutely straight and performed at a consistent speed to leave great edges behind. A projected laser guideline shows the user the precise path of the blade along the work piece, and simple controls let the operate start cuts with a single button press. The control panel also has a stop button, a separate emergency stop button, a laser power button, forward/backward buttons, and a toggle switch to control power to the entire machine.

The physical construction should make sense to anyone experienced with machine tools. The table is a small sheet of plywood onto which everything else mounts. Two hardened steel rods run the length of the table. The circular saw (a corded model from Makita) mounts to a carriage plate with bearing blocks that ride on the rods. A spring-loaded retracting wheel mechanism pulls the circular saw's power cable back and out of the way. The laser module mounts onto a small armature that allows for precise adjustment and the control panel box attaches to a desk lamp-style arm so the user can move it around.

On the electronics side, an Arduino UNO development board controls a stepper motor through a motor driver module. That stepper motors pulls the circular saw carriage back and forth with a belt, similar to a 3D printer. The Arduino controls power to the saw through a relay module. Limit switches tell the Arduino when the carriage reaches either end of the rail. The control panel contains arcade buttons and the laser comes from a standalone module.

There are a lot of ways to cut wood, but this automatic circular saw is a relatively affordable way to get great, repeatable cuts.