Just measured up mine.  The end diameter where the mirror goes is 1/2. But the rod tapers up to 11/16 at the base end.  It’s a pretty consistent taper.  The 13-1/2 is correct
		 
		
		
		
		
		
		
			
				__________________ 
				Jordan Baker 
RHLI Museum, 
Otter LRC 
C15A-Wire3, 1944 
Willys MB, 1942 
10cwt Canadian trailer
			 
		
		
		
		
		
	
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