I got a bit creative with the tensioning pulleys bc the elastic was so weak.
I realized after I built it that I shouldn’t have added the front lip bc it keeps the sled from reaching the bottom. I’m open to suggestions on how to keep plywood in place long enough to screw it down.
The regular frame has a 2x4 that sticks out in 2 places in the front about 1.5" so it will hold 3/4 spoil board and 3/4" thick cutting board. I shortened it so it is 1.25 so I can cut 1/2" without the sled catching.
So there is a second option. If you cut your lower rail to fit between the 2 legs, you can use it as a ledge that sticks out far enough to hold a sheet long enough to screw it down that won’t interfere with the sled movement down low.
If you remove the front lip, I recall seeing the other day someone put two short 2x4’s on the front bottom of the 2 legs, acted as short of a cap, but stuck out far enough to act as supports. They went from the floor up to the bottom of the plywood. If this doesn’t make sense let me know, I’ll try to remember where I saw it.
Take the front board, cut a notch in it and the legs where it rests, so that there is only 1/2 an inch sticking out for your working sheet to rest on. This gives you a full lip to rest your plywood on, but doesn’t prevent the sled from reaching the bottom of the board. It also adds some more stability to the frame.