Thanks for your response Dan, but you get the whole thing wrong. Sorry for making the confusion. I'm not interested in the SME mount, just use it as an example. What I really want to know is if I have an armboard for Graham2.0/2.2, can I mount another arm on it? I can see the 2.2 armboard isn't SME mount anymore, and it's round, so can I put a Linn, or VPI, or Triplanar arm on it?