Many, many years ago...a question came up on the old WOOD-on-Line Forums....about a replacement for those POS fences seen on most Job-site tablesaws....
Friend of mine had a DeWalt 10" Job Site saw....usual junk fence....
Iso. Triangle of plywood, with a factory 90 degree corner. Hardwood cleat to ride on the fence rail, thin enough to span between the top of the rail and top of the saw...set cleat on rail, tight against the edge of the saw's top. sit it in-line with the mitre gauge slot. Place the plywood on the cleat, align the long leg along the slot..2 short screws to attach it to the cleat. Next, a 1 x 3 was screwed down along the long edge, flush with the edge of the plywood...maybe a pass with a plane to clean that up..
Depending on YOUR saw...you can clamp it to either the old fence rail....or, in my saw, to the top of the saw. I add a piece of 1/4" plywood under the fence as a zero clearance overlay....
Also, this can be clamped to about any wood panel...laid out for use with either a router, or the circular saw to guide the cut....I can also clamp this to the old SKIL router table as a fence.
Takes 3 pieces of scrap lumber, maybe a 1/2 dozen screws. No glue was used..in case I ever need to replace a part...or, make a taller fence...
I made a jig, to hold a panel vertical...the jig can slide along the top edge of that fence....keeps me fingers out of the way..