REPLACEMENT OF HAMMER HEADS

Dear Placido,

Replacing the hammers is a very complex matter and the procedure cannot be described in a few words. Furthermore, the choice of the hammer rail depends on many factors and it is not always possible/advisable to install hammers that are simply copies of the old ones. Replicating the weights is as complex as the drilling, which must be performed with a gradual inclination while respecting the appropriate distances from the hammer apex. A machine is required to fix each hammer and allow the drill press to drill precisely. Lastly, the balancing of the keyboard is an expert task. In every piano, the possible weight reduction of the keys in relation to the return weight must be evaluated. Then, the hammers must be voiced beforehand on a bench before finishing the final voicing in the presence of the instrument. The hammers themselves must be finished in their tails with a particular tapering (in the case of the grand piano). The shanks (in the case of the grand piano) must also be prepared and their travel toward the strings must be checked for verticality. Everything must be rechecked after gluing, which must be performed by tapering the hole with a conical reamer and using natural hot glue. Gluing should be carried out with the help of a precision alignment tool. Much experience is necessary and many technicians, even after years, make many mistakes. For example, the striking points are difficult to determine; they are not always in a straight line, just as the inclination of the hammers in their resting position may not be perfectly vertical (this is because hammers with drilling at different degrees of inclination describe an arc in their travel toward the strings which is the result of a mathematical calculation, not a visual effect). Each hammer must strike the three strings or the two strings simultaneously, and any offset may indeed depend on how the hammer rises or on a non-uniform planarity of the strings.

Many other considerations emerge during the intervention, and therefore this must be performed by an expert technician. Proper equipment and precision tools are required....and considerable experience. Errors could accumulate and lead to an unsatisfactory result. In the case of the grand piano, the replaced hammer rail MUST BE ABSOLUTELY RETAINED BY THE OWNER while still glued to the shanks. You must demand its return. This is so that one can eventually trace back the relative measurements in case errors are made on the new one. And not just for this reason. One may also decide to install a hammer rail that is slightly different in brand, shape, felt compression and, therefore, in weight, but the original represents a part of the piano's identity. Regards,

Paolo

I thank you, Maestro Ferrarelli, always very kind and professional.

Good evening Maestro Ferrarelli, I purchased the hammer felts, could you please explain to me how to remove the old felts and how to glue on the new ones? Thank you very much.

Felts? You must mean the hammer "heads"..... We said that in the case of the grand piano, not the upright, they are mounted on new shanks. The old hammers must be left glued to the old shanks !!!!!! In the case of the upright (and also the grand), the hammers are removed with special extractors. Here too, it would be better to replace the entire piece—nut-strip-hammer—so as to leave the originals glued and intact!!! All this also because, in case of certain errors, one can trace back to the originals !!!!

Excuse me Maestro, I explained myself poorly, I mean if it is possible to replace only the hammer felt and its procedure. Thank you.

Some Houses do it (but I advise against it), but the procedure must be followed by a technician because the hammers must subsequently be prepared on the instrument

I thank you.

Maestro Ferrarrelli, I contacted the Abel company asking if they could sell me the wool felts for the hammer rail.... they replied that they cannot sell to a private individual but only to retailers or tuners. Can you give me some advice on this matter regarding the Abel company? Many thanks.

I think it is quite difficult to rehammer a hammer (from what I understand, since he only talks about felt) by oneself, especially on the part of a non-technician. Abel does it upon request; it is usually done on antique instruments where it would be extremely difficult to find an identical hammer (think of 19th-century Erards, with those particular hammers, with that particular play of underfelt).

You can have fun modifying the regulations, at your own risk (in the end, it's "only" a matter of having to call the technician and restore everything); but I would NEVER touch the hammer, neither by replacing it nor by trying to voice it. The expense to restore the previous situation could be very heavy!

It is not correct to provide further information. The Company has already responded. You must contact a technician! It is like asking: where can I buy an engine to change it in my car?

This Forum and this site were not created to encourage pianists to do "DIY". This is because, as Francesco rightly says, it could lead one to believe that everyone can perform any intervention on the piano. That is absolutely not the case. The technician's work, in the replacement of the hammer rail, represents more than 2/3 of the total cost. This is NOT because it constitutes a "markup", but because it remunerates a competence and professionalism indispensable to achieving a good result. The operations to be performed are numerous, with the aid of special equipment. Despite everything, with good competence and experience, one must be careful not to commit errors in shape, drilling, balancing, etc... errors that could nullify the good final result.

Therefore, I insist again, assuming your instrument truly requires a replacement of the hammer rail, I invite you, if necessary, to consult a skilled technician, who can also guarantee in writing the procedure of the intervention and the materials used.