John Tuttle asked for a simple formula for calculating the length of
tubing required for the run between tracker bar and stack.  I work
on fairground organs, so this equates to the run between the keyframe
and relay.

I work on the principle of the distance between the centre of a row
of keyframe nipples and the centre of the relay nipples.  I then
multiply by the number of keys.  This assumes that there are as many
tubes run at less than this length than there are run at more.  Thus,
on an 89-key organ the centre-centre distance might be 5 feet, and this
multiplied by 89 is 445 feet.  There are, of course, variables, so the
answer is taken with a pinch of salt, but I have yet never been left
wanting.

Regards,
John Page, UK