Here are some detail shots showing the pain in the ass that was.
Here's the making-of the spacers:
First up some dimensions:
Here are the tools involved:
The stages of construction - because I used a displacement style cutter I'm left with a large burr on the edge. I used a countersink bit to ream out the inner edge.
Note the funky looking tool on the right.
I made this little device using some plastic washers, some old hardware, a micro nut driver, and a broken dremel bit. (The nut driver was replaced with a drill for most of the sanding). When you tighten the screw the rubber expands ans holds the spacer nice and firmly to make sanding easier:
Repeat process 144 times... and as my joints stiffened and as the blisters grew in number I soon learned to loathe these items: