Pipe Nipples
I spent a lot of time planning how to get the shortest length of tubing,
tracker bar-to-pipes, with the least chance of kinking. All tubing has this
characteristic - PVC, natural latex, and thicker-walled rubber. The plan,
therefore, was getting the most direct "run" from the bar to the tubes. By
the way, I am using 1/4" and 5/16" tubing from
John Tuttle's player piano repair
company.
John suggests, page 14 of the construction manual, drilling a 45 degree hole
for nipple/tubing attachment. This does avoid some 90 degree turns,
but still requires a longer length of tubing, so I decided using curved or
bent brass nipples which I could "aim" at the direction of the tracker bar.
Bending Brass Tubing
Brass tubing is easy to bend if it is annealed. I annealed mine on the large
element of my electric range, for about 30 minutes, and let it cool enough
to handle. Then, I slipped a 1/4"or 5/16" ID fairly stiff tension spring
OVER the tubing, and found it would bend, without kinking or collapsing easily
to any arc (45 degees is the best bend). To get more consistent bends
(and save my thumbs) I devised a bending jig from scrap material, and the
task went fairly fast. (see pictures).
Then, I cut them to length with a cut-off wheel on my Dremel tool. I
did add a small plywood collar around the end to add a little strength to
the glue joint. Fibre washers would work as well.
To get the straightest run, I put the pipe board in place and marked the
direction to "aim" them to the cut-out in the pressure box. I put the
pipes in their respective positions on the board, removed them and glued
the nipples into place. |
