Wednesday, 5 November 2014

Regulating a Bluthner Action in a Bluthner Grand

Up until about 1918 Bluthner used their own Patent Action in their pianos. For a grand piano, this action was strikingly different from the more standard ‘Roller’ action. Regulating these actions cannot be done by trying to apply the procedure used for the roller action. 
These instructions are based on a leaflet produced as a guide to regulating these pianos. Some familiarity with these actions is absolutely necessary before attempting this work.

The necessary operations must be carried out strictly in the following order. The fitting of the Bluthner Action is based on a tough depth of 9 mm and a hammer-blow of 45 mm.

1. The hammer heads should be spaced exactly to the strings and the hammer-flange screws should be tightened.

2. Setting-up. The guide-pin of the abstract must be straight and vertical. The jack must be so adjusted - by means of the carriage which is screwed on to the key, that it drops quite easily under the nose of the abstract.

3.Set-off. The hammers should release 1.5 mm from the steel strings and half a string thickness from the bass strings - the set-off screws are situated on the hammer-rest rail.

4. Touch. Contrary to the Erard Action, the touch is made quite firm. The key is depressed slowly on to the touch-baize, after which the hammer should continue to rise 1 mm up to the set-off point. Only on striking the key strongly will the hammer be caught by the back check. (No after-touch).

Bluthner Patent Action
5. The checks must be cranked and spaced equally. The checks must each be parallel and central to the hammer woodwork. Now the hammers are checked. There is no special height but it should be about 24 mm above the hammer line. 

6. Drop. The guide pin of the abstract must move easily in the bridge leathers so that the abstract drops of its own weight. The repetition springs must move freely in the abstract felt clips and by pressure of either side of the right-angle spring, the drop is controlled. The hammerhead should drop down 3 mm after setting-off.

7. It is now necessary again to check the touch throughout.

The abstract
8. The dampers should lift when the keys are half depressed.

9. The damper shade-rail has to be adjusted so that when pressing down the sharps, there is very little play.

10. The coiled spring which is attached to the abstract should, in the normal position of the key, not rest on the jack, but remain about 3 mm from it. An even touch is of the greatest importance.

Technical File


1 comment:

  1. I have an unusual situation with a Bluthner Style 8 1902 with patent action.
    It is about the interaction between the jack, set-off and the checks.
    The checks come into play and hold up the hammers either when the key is held down on slow playing or with repetition when the rising checks come into contact with the falling hammer and before the next blow.
    In both cases where should the jack be. On slow playing I see no purpose in the checks. All would be accomplished if they did not exist.
    On repetition the it seems to me that the jack should be released to just below the nose of the abstract so as to enable the abstract and hammers to be projected upwards for the second blow.
    It seems to me that if the jack is not below the nose of the abstract when the hammers are in check the repetition will be propelled only under the force of the repeat or abstract spring.
    Any enlightenment on this matter and the interaction of these two parts of the action would be appreciated.