regulation problems in Aeolian era M and H 50"

[Richard Brekne]

Piannaman@aol.com wrote:

> Salutations,
>
> I've got some regulation problems on a 50 inch Mason upright from the 
> 70s.  I've worked on other Aeolian uprights of that vintage, and some 
> of them have the same problem.  
>
> The initial problem was that the keys weren't bottoming out on 
> punchings.  It seems that it's been that way since new(though they 
> bought it used).  There was a huge gap between the bottom of the key 
> and the punching when the key was depressed.  This led to hammers 
> blocking, bobbling, and a feel that could only be described as spongy.


I am not sure I understand here.... what is inhibiting the keys from 
bottoming out ?  Is there a stop rail at the back of the keys ? Is there 
something about the regulation of the action itself that meets a stop 
rail before the keys bottom out ?

You should be able to get a 9-11 mm dip range with no problems whatsover 
(outside of the obvious general regulation consequences of too deep or 
too shallow a key dip).Bottoming out should be no problem in this range.

If key height is way too high, then the bottoms of the keys will show 
over the keyslip rail yes.... I have a hard time seeing that anyone 
would set them so high as to cause them to not bottom out... but who knows.

Off the top of my head, from your discription so far it sounds like 
perhaps the dampers are hitting the stop rail before the key gets a 
chance to reach bottom. That would explain the spongeyness, and could 
account for bobbling. But if you force the key down you should be able 
to stress the damper wires enough to hit bottom... so I am just 
guessing.  Something, however, must be stoping the keys from hitting 
bottom and you need to find out what that something is.

Check all your regulation points first,  get all of those within 
acceptable tolererances before anything else.

Cheers
RicB

>
> At my last visit, I added punchings, and improved the feel somewhat, 
> but some of the bobbling is still there.  I also had to increase 
> letoff distance in some areas of the keyboard an unacceptable amount 
> to get it to work without hammers blocking against strings.
>
> I think that the main problem is that the key height is too great.  It 
> was somewhere around 70mm, though I forgot to write it down.  More 
> precise measurements are necessary, and they will be forthcoming after 
> my next visit there in January.  Blow distance is at 1 7/8(the only 
> thing in the piano that seems at spec...:-), but it doesn't seem to be 
> enough.
>
> I tried lowering the key height on a few sample keys by removing 
> balance rail punchings, but there was nowhere near enough aftertouch. 
>  Should I try increasing blow distance to 2 inches or more?  Any 
> ideas???  Haaalp??  
>
> Any input is welcome,
>
> Dave Stahl