Take two of the 12 inch
wide pieces of plywood and cut them down to 4 feet long.
Not exact matches
YOu could start with a
piece of 1/4 ″
plywood cut to fit your opening (ours is 31 ″ high and 42 ″
wide... but you'll want it to be exactly the height to slide under your banister on the stair and the width
of the stairs).
Cut a 12 ″ long 6-1/2 ″
wide piece of 1/2 ″ MDF or
plywood and secure it to the bottom
of the front
piece.
I had them rip the sheet
of plywood into four 11 7/8 inch
wide pieces.
The sliding feature allows you to cut a board that is
wider than the diameter
of the blade so it is great for building
pieces that use hardwood
plywood like our sideboards, desks and shelves.