akronharry wrote:
I don't have a router and would hate to buy one for a one time use. I will try to glue two pieces of plywood and screw them together tightly and then onto the steel and see what happens. Thanks every one.
You can always give that a "try", most likely will "work" but may be a bit soft compared to a full 3/4 plywood.
Another way to trim 3/4 plywood edge down to 1/2" is to once again clamp a straight edge the length of your plywood. Then set your circular saw depth so it leaves 1/2" of the plywood (in this case you do not want to cut all the way through the plywood).
Run your circular saw against the straight edge for your first "cut", then proceed to make the next cuts closer to the edge (each cut "overlaps" the previous cut slightly). If you need only 1/4"-3/8" it will only take a few passes. Makes a bit of a rough edge but no one will be looking at it (your just looking to slide the plywood slightly into the metal groove).
I have made a few cuts like that in the past when dealing with tongue and groove plywood. Sometimes you need only a narrow piece of tongue and groove plywood and when you cut the sheet it leaves a piece with no tongue and one piece with no groove.. So hence the homemade approach to making a "tongue"..