Bing, if you'll PM me your full name and address (or post it here), I'll send you a plan for making a shield from a 40 inch square of sheet metal. The result will be a conical shield with a square hole at the top that a 4x4 will fit through with tabs allowing it to be secured to the 4x4. Of course, in accepting the plan, you agree not to patent it and also agree to relieve me of responsibility if you injure yourself or someone else when making the shield. Sheet metal is springy and injury is very possible.
