The best material for making chime tubes is "bell brass".  It is
available from brass and bronze suppliers in a wide variety of
diameters and wall thickness.

It is actually fairly simple to tune if you cut the tube with a chop
saw fitted with a metal cutting blade.  You'll need a strobe tuner as
well.  Tuning is slightly different if there is a cap at one end of
the tube: it changes the length of tube needed for a particular pitch.
If you can clamp the tube at dead center and strike it, the tube will
give you the fundamental frequency without dampening the vibrations
too much.

I have seen the large orchestral chime tubes from Musser Division of
Ludwig Drum Co. being tuned.  For symphonic orchestra chimes the
overtones are "tuned in or out", meaning that the tube is crimped at
exact points to make it slightly out of round and either eliminate or
accentuate a particular harmonic.  This gives chimes their fundamental
tone quality.

Deane Prouty