It should have been moveable(adjustable). But 1 mm wider is an adjustment.Wow. Your manual says it's adjustable, but it isn't. Now you're blaming the customer?
Why does your manual and advertisements say it's adjustable (and is 1mm too large to consider an adjustment)? Why won't the nut turn? Is that my fault for trying to do something your manual says you can do?
As said above, the head was adjusted for our plates. It should be easily adjustable after squeezing the sides of the clamp together. See the video on my site rodklukas.com.
I appologize if it appears to be stuck. Not our usual delivery.
I will say, that the 8501003.1 with the knob is best for those with mixed manufacturers plates. Please contact me or Precision Camera Works for follow up. I am available most times or will get back quickly if not.