On donderdag, mei 8, 2003, at 22:01 Europe/Amsterdam, Isaac OLEG wrote: > Hello Andre, > > The instruments in the conservatory are shaped every year a little. > > I've heard of a shaping method with a small wood plank and filing > paper 80 grit on it , that is supposed to be the standard method used > at Yamaha France, and that allow to "uncap" the top of the hammers > very fast (even the bass hammers). No finishing with finer grit, a > friend is supposed to show me that trick someday, did you see that > method ? Sure Isaac, 'Hand filing' is the old method and still in use by many technicians in many factories. Using # 80 is a very fast method and very dangerous. I prefer 3M #40 as it has more of a polishing quality but still has 'teeth'. In that case you 'do something' to the surface of the crown and underneath the crown without really taking off whole chunks of meat. > Indeed filing hammers in the piano mean being in a very uncomfortable > position, and if the marks are deep a lot of work is due after filing. > Is not it better to give the hammers new power before filing them , > then we probably can shave less felt, as we work on a tensioned > material. then final top voicing is remaining only. Nah... If it is a healthy hammer, it has enough power in the cushion area and in the 'basement' or the battery. The problem with grooved hammers is that a. the crown is damaged with grooves and broken fibers and b. the top of the hammer has hardened a lot during the previous time of 'banging'. Filing away the grooves is not such a problem but the real problem lies in symmetry. If we file the crown, the pear shaped hammer becomes an apple. A STW hammer has per definition a diamond shape and at worst a pear shape. If we just file the crown the hammer will become indeed a pear and when the grooves have become very deep the shape of the hammers become apple shaped. This is the worst that could happen to any hammer but a STW in particular. So, whatever we do, if we start filing we must not only (partly) file away the grooves, but we must also take care of the final shape of the hammers, like sculptures. Symmetry is of the highest importance, and to do this job right asks very much of even the best technician. It requires very much experience, a carpenters (craftsman's) eye, a very steady hand and a damn good technique. The 'shoeshine' method is the only method really as the other manual method with the filing paper glued on a small piece of wood will cause irregularities and unnecessary damage. A Yamaha hammers has a pear shape basically like Bösendorfer, and Bechstein uses the egg shape. If we don't know this we'll ruin the character and thus the sound structure of the instrument. It again shows how extremely sensitive hammer filing is, not to speak of the final voicing where we eliminate 'noise' and fit hammers etc. I myself have learned my lessons by having ruined countless instruments in the past. Today I take my time and I need all my experience to do a 'decent' hammer filing job and I try to avoid all that filing as much as possible for reasons I tried to describe before and above. > > Friendly greetings indeed, > > Antares, The Netherlands see my website at : www.concertpianoservice.nl
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