When making a homemade table saw with a circular saw, one of the problems we will encounter is what to do with the slot through which the saw blade protrudes. It’s not a big problem if we always intend to leave the blade at 90 degrees, but if we occasionally use the blade tilted, for example, at 45 degrees, having two slots side by side on the table doesn’t seem the most suitable (or aesthetic). One option is to use inserts with the slot adjusted to the thickness of our saw blade.
In the video, we see the procedure I used: cut a large slot to allow the blade of our circular saw to tilt and also facilitate changing the blade, rout a recess around it, fit the insert, and cut the slot in the insert. Note that we will need an insert for each blade tilt we desire, typically for 90º and 45º.
Watching the video, you might think routing the recess almost freehand can be complicated, but I’m sure if you practice a bit beforehand and cut the perimeter with a cutter, you’ll be able to do it without much trouble. Another option could be to place a frame of strips all around the slot to guide the router and avoid overdoing it. Then you would adjust the insert to the routed recess. Each person can choose the system that seems most comfortable to them.
If the table saw you have is not homemade but bought, it’s also advisable to make adjustable inserts to the thickness of the cutting blade, as most commercial table saws have a slot much wider than the thickness of the blade. The advantage of the insert is that since the slot is so narrow, it helps contain the splinters that would form when the blade cuts, as the blade cuts somewhat by “pushing” the wood down against the table. Since the insert holds the wood around the cut, it largely prevents splintering, resulting in much cleaner cuts.