hosted on condor3913
 Mechanical Music Digest  Archives
You Are Not Logged In Login/Get New Account
Please Log In. Accounts are free!
Logged In users are granted additional features including a more current version of the Archives and a simplified process for submitting articles.
Home Archives Calendar Gallery Store Links Info
MMD > Archives > May 2016 > 2016.05.04 > 06Prev  Next

Rotary Pump Makes the Grand Piano Shimmy
By John A. Tuttle

Hi All,  As two authors noted yesterday, the 'shimmy' problem is an
imbalance in the pump.  To verify this, you must first disable the
spill valve by inserting a small nail in the spill valve spring which
prevents the valve from pulling open under tension.  Then connect
a 'Tee' connector to the to the supply fitting.  One leg of the 'Tee'
gets connected to a vacuum gauge and the other leg gets connected to
an open hose with about a 3/16" leak.  That 'safety' leak will prevent
the pump from locking up or bogging down.  Now run the pump.  You will
clearly see the imbalance in the movement of the gauge.

Most likely, as another author said, the problem is that one or more of
the bellows is creating more (or less) vacuum than the others.  However,
anything that creates more or less resistance in one or more of the
bellows will cause the pump to vibrate -- like a cylinder in a car
engine that has a bad valve, bad rings, bad crank bearing, etc., etc.

John A Tuttle
Brick, New Jersey, USA

(Message sent Wed 4 May 2016, 04:08:45 GMT, from time zone GMT-0700.)

Key Words in Subject:  Grand, Makes, Piano, Pump, Rotary, Shimmy

Home    Archives    Calendar    Gallery    Store    Links    Info   

Enter text below to search the MMD Website with Google

CONTACT FORM: Click HERE to write to the editor, or to post a message about Mechanical Musical Instruments to the MMD

Unless otherwise noted, all opinions are those of the individual authors and may not represent those of the editors. Compilation copyright 1995-2023 by Jody Kravitz.

Please read our Republication Policy before copying information from or creating links to this web site.

Click HERE to contact the webmaster regarding problems with the website.

Please support publication of the MMD by donating online

Pay via PayPal

No PayPal account required

Translate This Page