About the Diamond frame Patrick said,
> The mitering of the tubes at the BB is a case in point.
Patrick, The inside of the shell on the Diamond is nicely finished. The "mitering" inside the BB is/was probably finished up with a die grinder with a rotary burr and possibly a flap wheel of some sort, it has that tell tale smooth look.
The misnomer of looking into the shell to see how the rest of the frame is mitered is a carry-over from the old days when cheap bikes tubes were simply lopped off and stuck into the shell.
I would be willing to bet these days almost any decent bike will have nicely mitered joints.
peter weigle
lyme, ct.