Action rebuilding question

[Ron Overs]

Hi Brian and list,

Your most recent description fits the Bluthner patent action nicely, 
Stephen 
Birkett's suspicions were correct.

>I've never seen an action like this one before, so I . .(will) . .  describe 
this thing.
>
>The key sticks start out at the key front looking quite normal.
>Looks like a rocker set up rather than a capstan set up on the back side of
>the key.  So far so good.  Low friction, nice feel. 

Typical of the Bluthner Patent action. The rockers are used for adjusting 
the 'lost motion'. 
The hammer shanks sit on the hammer stop rail in this action.

>There really isn't much
>of a wippen to speak of.  The jack appears to fasten to the key at the
>rocker, and pivot away at the top (under the knuckle) for the escapement.
>There's more to it in the middle of this jack for the escapement, but I
>can't put my finger on the mechanics that trip it at the moment. 

The let-off buttons are located directly behind the jacks, and the jacks 
let-off 
towards the rear of the action.

>Two springs
>were notorious.  The first was on the key starting around the front of those
>rockers and going back into the jacks.  I would guess this was their version
>of a repetition spring. 

Yes it is. But since there is no drop screw, or any other device, 
to prevent the hammers from rising out of check to the strings, 
you cannot set the spring tension so high that the hammer rises. 
The tension is set so that the hammer just tries to rise, but doesn't.

>The second was a little spring resembling the
>letter "J" (laid on it's left side) coming out horizontally from a rail? and
>having a little button on the curved end which acted as a jack stop, and
>perhaps another function?.  I don't remember a lot of detail about the
>back check set up, and I'm a little fuzzy on the exact jack set up.  It was
>unlike anything I've ever seen before, and I wasn't able to 'play with it'
>for long enough to get a good idea of how it all fit together.

>The gentleman had some desire to do parts replacement due to the wood of the
>action becoming more brittle and more prone to breakage.  But I know that
>doesn't necessarily spell the death knoll for this action.

Bluthner patent hammer shanks are available from Renner 
(not sure about Renner USA, but from 
Germany certainly).

> It was fascinating to see an action that was
>built in about 1905 that had the look of something than might have been
>built in about 1875.  I'm told that the European pianos retained the 'odd'
>or 'non-standard' action types for about 30 years longer than the (what
>we've come to know as) standard actions of today.

Julius Bluthner designed the Bluthner patent action and used it for most 
of the 
grands he manufactured up the turn of the century. He started using 
modern style 
repetition actions around 1880. He used both actions for grand piano 
production 
until 1906, when his patent action was phased out.

Yesterday you asked the list if it was possible to replace the Patent 
action with 
a modern action. This is possible if you are prepared to make a new 
keyboard as 
well. The keys on the patent action are splayed along with hammer shanks 
from bass to treble.

Should you decide to rebuild the Patent action (set up they play very 
well - they just don't repeat 
quite as fast as a modern repetition action), it may be worth noting that 
the action leverage ratio 
is not uniform from bass to treble. It is about 20 years since I rebuilt 
one, so I cannot remember what 
the ratios are. But in any event, you will require less key dip in the 
treble when compared to the 
bass section.

Hope this helps.

Ron E. Overs
Overs Pianos

Email: ron@overspianos.com.au
Website: www.overspianos.com.au