warped main action rail?

[David ilvedson]

Hi John,

Welcome to the Wurlitzer booby trap.  I had the exact same 
problem some years ago.  I think the action was forced into an 
incorrect position then regulated at the factory.  When I pulled 
it and re-installed correctly, I had to do a bunch of regulation.  
It made me look like a fool.  

David I.

From:           	"John M. Formsma" <jformsma@dixie-net.com>
To:             	"PianoTech" <pianotech@ptg.org>
Subject:        	warped main action rail?
Date sent:      	Mon, 28 Feb 2000 10:44:28 -0600
Send reply to:  	pianotech@ptg.org

> List,
> 
> The piano is a Wurlitzer studio console approximately 25-30 years old. I
> removed the action to replace the bass strings because most of them were
> universals. While the action was out, I did the following:
> 
> --filed hammers
> --tightened action screws
> --tightened action bracket screws because they were shifting a bit in my
> hands The bottom ones were not needed tightening as much as the ones screwed
> to the spring rail.
> 
> When I put the action back, it was difficult to get back into place. I.e.,
> it felt like I had to put unnecessary pressure on the brackets to force them
> to fit back on the action bracket bolts. I checked to see that all the
> brackets were properly fitted on the bottom ball bolts, and they were, so I
> thought little of it until...some of the notes from about F3-D5 barely
> sounded because their dampers were not being activated properly. Since the
> action did not seem to fit into place correctly, I assumed that maybe it had
> been put back wrong. Took it out again, put it back in. Same problem. Took
> it out again, stared, scratched, etc., put it back in. Same problem, so I
> adjusted the spoons per note, put it back in. Better, but not at all
> satisfactory. In the midst of taking the action out and putting it back in,
> I noticed that if the two middle action brackets were not all the way up
> against the bracket bolts, the dampers worked much better, allowing the
> notes to sound. Scratching a bit more, I took the action out again...this
> time to stare (and swear). Noticed after some staring that the main action
> rail looked warped--bowed in the middle with the bow towards the keyboard.
> OK, so I go to put the action back in, decided to test, but noticed that the
> bottom ball bolts on the extremes were both leaning towards the soundboard.
> (Would make sense if the rail were bowed.) Bent them back where they were
> more supposed to be (visually), put action in. Same problem. Then I loosened
> the two middle action bracket screws which attach them to the main rail. The
> notes begain to sound normally--i.e., they were not damped all the time. So
> I figure that the problem must be a warped main action rail. Does this sound
> like it?
> 
> If this is the problem, what is the solution? I have thought that shims
> could be put between the rail and the middle action brackets, forcing the
> bow out of the rail. Or, what might be better if it would work, to take two
> pieces of thin metal, drill a hole in one of them, insert one metal plate in
> between the rail and side of bracket. The other adjacent to it (also in
> between rail and bracket) would have a hole that is threaded, allowing a
> metal screw to be inserted and screwed in to contact the back plate, forcing
> the bow out as needed simply by turning the screw. The ability to make
> adjustments would be better this way, right?
> 
> This is a brand new problem to me, and I've never had to think of a
> solution. Would this work? Have I misdiagnosed the problem? Any suggestions?
> One other thing that may help in diagnosis is that there was lost motion,
> which felt more particularly acute in the middle section. This could be
> caused by a bow, right? However, there was some lost motion throughout.  I'm
> not done much on the regulation stuff yet, so I will get a chance to learn a
> bunch on this one, I'm sure.
> 
> What I did was to leave the two middle action bracket screws untightened to
> minimize the bow and allow "normal" sound. I have to go back to retune the
> bass strings, and will need to solve the problem I have discovered at that
> time.
> 
> Any help would be so greatly appreciated!  Thanks.
> 
> John Formsma
> Blue Mountain, MS
> 
> 


David Ilvedson, RPT
Pacifica, CA
ilvey@jps.net