It is common practice to use the circular saw to rip down sheets of plywood.
But if the cut-off piece is unsupported, it can sag -- sometimes even
breaking off and tearing the veneer before finishing the cut.

To prevent this problem -- cut a two inch long by 1 inch wide strip of 1/8"
hardboard - and drill two holes to insert a couple 1/4" dowels spaced 1"
apart.
After starting the cut on sheet goods, slip the support into the saw kerf,
and it keeps the cut-off piece of plywood from sagging.

>Pat Taylor KIWTG