I just put my 39 pu windshield back together. Like 35Ragtop stated, the square bars get stuck in the frame. I removed two screws from the upper half and drilled out the other two which had the heads snapped-off from previous attempts. New stainless screws are available from bolt warehouse. I used a wood 4x4 and 1/2" threaded rod to push the frame halves apart. I routered a groove to follow the curve of the upper frame, some heat, lube and malletizing and it finally came apart. The frame is fairly soft steel and will warp easily so be gentle. If I was doing it again I'd spend more time making the tool to push the frame apart. Also, when it goes back together, do not leave any burrs, no matter how small. That little mistake cost me a $100 in new (again) glass and a week. Your machinist doesn't want the job apparently, time for plan B.