It took John Heisz almost nothing to make this table saw: attach an un-modified circular saw to the bottom of a piece of plywood, slap on some legs, and build a fence. The fence is the most complicated part, and yet it’s nothing more than a home-made clamp that pinches the rail when you turn the knob.
I wouldn’t have though to accommodate the blade guard by cutting an oversize slot through the table. It’s a clever idea that allows for a guard (one that only works when the blade isn’t cutting) and makes it possible to remove the saw and use it in the normal manner. The downside of the oversize slot is that it creates opportunities for stock and offcuts to snag or fall through.
This saw was clearly thrown together—the legs are not even diagonally braced. Still, except for an on/off switch the important parts are all there. I assume Heisz used a zip tie or something to hold the switch on and activates the motor by plugging it in. It wouldn’t take much to add a switched receptacle to the table and control the saw with a rocker switch.
That such a simple machine works shows how little one actually needs to rip stock. Seeing this sort of thing makes me wonder why so many companies make tables for routers but none (that I know of) make them for saws.