I have replaced the lead tubing in a player piano with brass tubing.
I got it at a hobby store; it comes in different lengths and widths.

I just cut it in around 1" lengths and after having removed the lead
tubing I drilled an appropriate hole in a piece of dowel which had been
placed in the hole, and secured the tube in place with either CA glue
or burnt shellac.

There also used to be brass reducing adapters to allow the proper size
tubing be attached to the larger holes that the lead tubing had been
removed from.

Even although lead tubing is available, I prefer to re-tube with the
replacement tubing they have.

John Ross