Was working on my Nikkor 50mm f1.4 non AI lens today to make it into an AI lens so I can use it on my F5 and D700. Well everything was going just swimmingly until I went to put it back together. Then I found I had cut out the wrong side of the ring! Duh. Oh well can still mill out the correct side tomorrow just won't look as pretty. Jeez!!! 
