woodworking bench mdf top The 4’x8’ mdf sheet is cut into two 64" by 20" sections and two 32” x 20" sections. the two smaller pieces will be butt joined and sandwiched between two 64 x 20" pieces. do try to find the 1" mdf, it’s not fun to handle but less work in the construction. here are a few tips that will make your mdf bench top last longer.. I think mdf makes a great top for an assembly table...