It Looks So Advanced!

I mentioned that the tailpiece adapter did not have an adequately square hold on the extension tube and that I thought it might be partly because the adapter was only 1/2" thick preventing a sufficient imposed parallel between walls and tube.  (I might also have bored the interior hole slightly too large.) So a 1" thick block of Delrin arrived today and I have the mill hard at work.  I will try for a near-interference fit on the tube.

I bored the adapter hole  004" larger than the extension tube OD.  This was a near-interference fit, so i took a file to the interior of the hole. Now it is .005" larger and the extension tube presses or pulls with some slight friction.  Next step is 6-32 tapped holes for mounting it to the PVC tube and an 8-32 tspped hole for the thumbscrew to hold the extension tube