[V12Bill]

The shaft on my 1939 PU looks like yours with the hex shaft. The bolt on wiper arm that I have is knurled on the inside. If I have the nut tight enough, the wiper cleans the windshield. As time goes by, I think that the nut loosens and the motor shaft spins inside the wiper arm. Since the shaft is so small I hesitate to put umpf on the nut. I too, would like to get the proper arm. Maybe some silicon caulking compound will fill the gaps.