I'm just starting work on a Standard player piano stack.  While looking
over the four tubes from the tracker bar to the tracking valves, I
noticed one tube was cracked off about 3/16" above where it enters the
top of the valve assembly.  The tubing appears to be white, with a gray
exterior.

There does not appear to be a brass nipple at this point.  What remains
of the tubing just seems to flare out against the wood.  How is (was)
the tubing connected to the wood?

Mike Blackwell