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 > September 2010 > 2010.09.09 > 05Prev  Next


Securing the Dowel to the Threaded Pushrod
By John Phillips

Hello MMD.  The link between a striking pneumatic in an Aeolian player
action and the wippen upon which it acts is a brass rod, threaded at
the top end.  Screwed onto this thread is a cylindrical wooden finger
(or pitman, I believe) and it is the top of the finger that contacts
the underside of the wippen.  I realize that this is very well known
to anyone who has had anything to do with an Aeolian action.

The fingers can be adjusted until there is just no gap between the
finger and the wippen by screwing the finger up and down the brass rod.
This is a rather tedious process; it involves putting the upper action
back into the piano and then inserting an arm under the action and
feeling for the bottoms of the pneumatic fingers.  When one is found
it's necessary to push it up until the corresponding hammer starts to
stir from the rest rail.  Then one has to guess at how far up the
pneumatic finger moved, note that down and move on to the next
pneumatic.

After this is done, eighty-eight times, one takes the upper action back
out of the piano, which in my case involves accosting a neighbour to
carry one end, and put the action on a stand, where one can screw all
those fingers up and down their brass rods.  Then the action goes back
into the piano for a check to see how close to perfection attempt
number one got.

I'm now on iteration number five and I think things are just about
right.  My back sincerely hopes so.  I should mention that I've been
adjusting those fingers so that if I push the relevant hammer against
its string(s) and let it go, I can just feel a slight thump transmitted
down the brass rod as the hammer falls back onto the rest rail.

When I pulled the action out, three years ago, I noticed that the
fingers belonging to the lower valve chest were screwed a long way up
the thread on their brass rods.  Not surprisingly that's the case now.
In some cases there is a lot of thread showing and some of the fingers
are rather too easy to turn.  This worries me somewhat.  For the first
four fingers at the bass end of the action, I have tried taking the
finger right off, putting a bead of burnt shellac on its bottom, and
then screwing it back on.  I'm hoping that the shellac will reduce the
likelihood of the finger working its way up or down the brass rod when
I can't get at it.  But I certainly don't want to glue the fingers
permanently in place.

If anybody has any comments on the shellac "solution", I'd be delighted
to hear them before I tackle all the other fingers.

John Phillips in Hobart, Tasmania


(Message sent Thu 9 Sep 2010, 12:40:24 GMT, from time zone GMT+1000.)

Key Words in Subject:  Dowel, Pushrod, Securing, Threaded

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 1995-2024 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

Please Support Publication of the MMD with your Generous Donation

Pay via PayPal

No PayPal account required

                                     
Translate This Page