In my neighborhood, people buy a lot of ready-to-assemble particle board furniture. It's designed to not be repaired, so when one part breaks, they drag the whole thing to the curb. There's usually not much damage—one or two broken panels, maybe a caster, a drawer pull, or some other piece of hardware broken off—and the other panels almost like new. Perfect for building something, just not the same thing. Apparently they can afford to keep replacing their furniture, and most of them don't mind my picking up their cast-off pieces. Sometimes they even help me load them. So I have free pallets, free particle board, and occasional pieces of dimensional lumber people put out with the trash.
I was cutting slide members from free particle board, but my cuts with a circular saw weren't very straight, and my miter saw only has 8 inches of travel. Add the portion of the blade that extends into the slot in the table, and you can make a cut of about 13 inches—fine for cross-cutting shelves or dimensional lumber, but rather limited for cutting large rectangles of panel products. I don't have money or space for a table saw, and I wouldn't use it all that often anyway. While looking at panel saws, track saws, and various DIY options on the web, I found this:
The two boards on top guide the circular saw, the hardboard indicates the exact location of the cut and width of the kerf, and the bottom two boards provide an edge to hold the work perpendicular to the cut while holding everything together.
I sketched out some ideas based on what I had on hand and what I wanted to do. A 4 foot cutting length would handle anything up to a half sheet, more than enough for this project, but a set of shelves 6 feet tall turned up on a curb, so I used it.
I thought it would be good to post a CAD file. I read blueprints at work, but my last drafting experience was a paper and pencil class in 1990. Mwmkravchenko from Gingery Machines Main Group recommended starting with LibreCAD. So here's my first-ever CAD drawing: Track Saw. Let me know if you find errors.
ETA: I forgot to allow for the length of the shoe ahead of the blade so I could cut all the way to the bottom of the stock. I added a board 3" x 5/8 " x 30" as a spacer. I had assumed it would be easy to clamp the stock in place, but that didn't work very well. Wedging scraps of hardboard between the panel guides and the stock worked better.