warped main action rail?

[Richard Brekne]

Question... did you tighten the action mount screws with the action mounted in
an action swivel ?? (one of those handy dandy jigs from old APSCO for working on
actions). If so then thats probably your problem and it is easily solved my
loosening the action bracket screws just a bit then re-install momentarily in
the piano so that it fits easily, then take out and screw tight once again. ...
Otherwise... grin... then perhaps you got some work in front of you.. If the
main rail is warped you should be able to identify that easily enough by
measuring out from the strings at several places up and down.. a warp will show
up quickly enough ... but really.. if its a warp that is causing the problems
you describe.. you'd think you'd be able to eyeball the problem..

"John M. Formsma" wrote:

> 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

--
Richard Brekne
Associate PTG, N.P.T.F.
Bergen, Norway