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MMD > Archives > September 2013 > 2013.09.06 > 01Prev  Next

Automotive Rubber Tubing Isn't For Player Pianos
By John A. Tuttle

Hi All,  I have two major gripes with automotive hose and tubing.
One, if the tubing has a rated dimension of (let's say) 1-1/4" ID
(inside diameter), it has an ID of 1-1/4".  You might say, "Well,
so what? Isn't that the way it should be?"  And I would reply, "Yes!
And that's perfect for a car, a truck, or a boat.  But we're not
talking about using the hose or tubing on cars, trucks, or boats."

Secondly, the wall thickness of tubing and hose that's made for cars,
trucks, and boats is almost always thicker than the same size tubing or
hose that's made for player pianos.  And, generally speaking, it's also
stiffer because it's reinforced to withstand the pressures found in an

Twill [-covered] tubing for player pianos should be very flexible
because it is often placed between two stationary devices that are
only a short distance from each other.  Also, unlike the flanges that
are in a vehicle, the flanges in a player piano are held in place with
small wood screws, not nuts and bolts.  So, if you get too aggressive,
you'll rip the flange right off the device.

For me, the most serious problem with automotive tubing is the inside
diameter.  That's because the various fittings that are used in a player
piano are quite exact with regards to their size.  In other words,
a 7/32" elbow or straight nipple measures exactly 7/32".  So, if you
connect a piece of tubing that's exactly 7/32" ID to a fitting that's
exactly 7/32" OD, you don't end up with an air-tight connection.

On top of that, the connection isn't "snug".  So, over time, even a
slight tug or vibration on the connection will cause it to come apart.
Tubing and hoses for vehicles are designed to require hose clamps of
one sort or another.  Such is almost never the case with player pianos.
(One notable exception is the 1-1/2" ID tubing in the Aeolian Themodist
player, which uses a coil spring-type clamp to prevent leakage as the
tubing ages.)

It's for the above reason that all good player piano tubing has an
inside diameter that is slightly smaller than the rated size of the
tubing.  For example, tubing that's rated at 9/64" has an ID of 1/8",
and tubing that's rated at 1" has an ID of 31/32".  And, since the ID
of good player piano tubing is always smaller than the OD (outside
diameter) of the fitting to which it will get connected, there is
never a need for any sort of a clamp, adhesive, or sealer.

And, while it's true that a couple of manufacturers used sealant to
secure tubing to various fittings, they are the exception rather than
the rule.  Regarding hose clamps, they have damaged many vacuum supply
flanges; like those that were made out of materials other than steel
or brass.

While it's absolutely true that good player piano tubing is
significantly more expensive than tubing for other applications,
it's also a fact that it's different from all other types of tubing.
Also, good player piano tubing is going to continue to get more
expensive because it's getting harder and harder to find manufacturers
who are willing to make the small quantities that are required to fill
the demands of a constantly shrinking industry.

In closing, I can't say that I've never used automotive tubing in
a player piano.  Early in my career, before I could afford to stock
every size of tubing for every type of player piano, I'd run to the
auto supply store for a foot of this or a few feet of that.  And,
I broke off or crushed my fair share of flanges and fittings (which
I then had to replace) before biting the bullet and getting the right
supplies for the job -- even if it meant delaying the job for a week.
In hindsight, it was a learning experience, and now I pass my experience
along to you with the hope that you'll heed my recommendations.

John A Tuttle (sells player piano tubing to the general public)
Brick, New Jersey, USA

 [ MMD articles about tubing (all types) are indexed at
 [  -- Robbie

(Message sent Fri 6 Sep 2013, 15:53:01 GMT, from time zone GMT-0400.)

Key Words in Subject:  Automotive, Isn't, Pianos, Player, Rubber, Tubing

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