Good jig-making Fred, I hesitate to think what you could build with a full day off! :>) I'm at the Banff Centre until the 18th, where we have a 1920's Mason & Hamlin A, pretty much identical to another one I have back in Manitoba. Both have damper systems that seem overly stiff, to the point if you don't take the pedal to bottom, encountering the underlevers at escapement pretty much rules out any chance of pianissimo notes sounding. Needless to say, there is no benefit regulating damper lift for anything earlier than 1/2 of hammer travel with these actions. (pedal and tray springs are also overly stiff.) So the other night I pulled the damper action on this one and weighed underlevers with and without springs, by resting them horizontally on a digital scale. I measured 25 -30g w/springs and 14g to 11g w/o. Roughly speaking, the difference between 3 leads or 2 in a lever was about 2 grams, so between regulating springs and leading pattern, it should be fairly easy to taper damper sytem resistance to match the keyboard. It's good you mentioned tri-chord resistance, and there is also the matter of mass with partial dampers at the break. But before I go over complexifying things here, I think it's just good that the "forgotten" action is actually being considered as a significant component of piano touch. With practice, it's possible to remove the dampers & d.action, clean, treat friction, check centre-pins, tighten leads, treat wires and guide rail, re-install and time lift, in the time it takes to do a normal tuning call (1.5 -2h). Most pianos will be getting this "day-spa" treatment for the very first time, and even new pianos will feel remarkably better as a result. As for the Mason, the damper-lever springs actually seem to have gone missing!(?) My conscience can live with that. ;>) The trap springs were also shimmed/tilted with a couple thick cardboard punchings to reduced pedal resistance. Now the intrument plays quite nicely, and I can hardly wait to give my Mason back home the same treatment! best regards, Mark Cramer, RPT Brandon University The Banff Centre for the Arts -----Original Message----- From: Fred Sturm <fssturm at unm.edu> To: College & University Technicians <caut at ptg.org> Date: Fri, 10 Dec 2010 10:09:31 -0700 Subject: [CAUT] damper touch weight In an earlier post in the friction thread, I described a device I had imagined to measure the weight of the damper as felt at the key. I had a little time to spare between access to rooms, and put one together. I think it took me all of ten minutes. A base about 1x4x8", a "balance rail" scrap of 1/2" plywood, a lever about 2' long, 1/2 x 3/4" (I think scrap from a strip used to hold hammers in place during shipping), a couple pedal brackets, a standard .146" balance pin. I glued a little scrap of wood on one end of the lever as a platform for weights - not really necessary, but nice - and then drilled a hole in the lever at the balance point. A couple drywall screws to hold the brackets, driven in with an electric screwdriver. It works very nicely. I tried it out just to see what I'd find, and a couple things jumped out at me. First, there is quite a bit of force needed to push trichord dampers out of the strings - as much a 5 gm. Even when trimmed nicely and precisely to the bottom of the strings there is a significant amount, though the difference between well- trimmed and not trimmed is noticeable, also between well-trimmed and just shy of well-trimmed (0.5 mm below the string line). On the concert instrument, where I have taken a fair amount of trouble to have the dampers well-regulated in all ways, I found a range from about 20 gm to over 30 gm top to bottom, and some zigzagging along the way in the 5 gm range. On a B that I had replaced action parts and damper felts on, but had only slapped the dampers in and regulated them for lift and to be sure they damped (fine-tuning put off until time allowed), I found much larger zigzags, 10 gms from one to its neighbor in a quick sampling. I suspect a lot of it had to do with some wires leaning on bushings, others not, but won't know until I have time to look more carefully. Bottom line, I think this is a good thing to look at, a significant element in the touch of a grand. PC100011.JPG PC100015.JPG PC100017.JPG Regards, Fred Sturm University of New Mexico fssturm at unm.edu
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