Hi Joe: I don’t have all the answers, but I’ll help where I can. Some of this is trial and error for me, without hard and fast rules other than steal from the best. You are correct about the barrels – it’s one bend to do the prep wire bends before gluing on the dampers and that is where the time saving is. If you have done that part well, there is less bending once the damper is glued to the barrel. And by the way, I do this without the hammers and shanks on the piano yet, just like the factory, it’s light years easier to work on that way. As for optimal configuration, here is what I find to be best, and why: For the one or two notes at the break that will require overdampers, I use a one trichord for the damper (that’s all there is room for) and a small flat for the overdamper. Above that, I use a trichord at the top and a flat at the bottom in a split damper configuration. The tri is at the top so that you can see it to adjust it. I’ve played with as many as 3 small trichords about ½” in length, but I find the combination of tri and flat to be best because we do not usually have agraffes that control spacing. As you know, plain wire does not always stay put. Therefore, the flat in combo with the tri and your best wire spacing gives you a bit of a fudge factor to accommodate these small variations in spacing. I have no hard and fast rule for when I switch from tri and flat to all flats. If I am buying damper blocks with the felt glued on, I switch when the set does (how’s that for an answer?) If I am making the dampers, I go up 10 or so from the break with the combo before going to all flats. No rule here for me – it’s what works, just like grand damper work. If the flats don’t do the job, I can add a trichord, but that is rarely a problem. I do not know optimal lengths. I find that the 62 mm? length in the bass for the Renner 3 piece monochords and bichords seems to work well (Is that the right length for the Renner damper? I am not at the shop and doing this off the top of my head, so correct me somebody if need be). I’ve made bass dampers longer without an improvement in damping, and you run into issues of lift at the bottom of the damper – the damper is pivoting on an arc and there is less lift closer to the axis than there is further away. So you run the risk of not clearing the string at the bottom. I do like 3 short pieces over 2 long ones, because the smaller pieces can conform to the string more readily than a longer one, thus shutting off more quickly. As for the knit butterfly flats vs plain flats, I prefer plain flats of short lengths because I find it conforms more readily to the string. If the felt is hard, I think the butterfly makes it worse, not better. It is very important to have high quality felt. If I am making the pieces up, I often use good quality grand felt where I can. I don’t know an optimal ratio for the length of each piece in a paired damper, only that shorter pieces of high quality felt seem to work better, at around ½” or a little longer. For me, this is pretty empirical, going from what works well on other pianos and making small changes as needed. Others can be more theoretical if they have the knowledge to share with us. But my configurations are results driven. I hope this helps. Will From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Joe DeFazio Sent: Thursday, February 10, 2011 3:08 AM To: pianotech at ptg.org Subject: Re: [pianotech] Replacing dampers on a Steinway Upright I have gotten some useful information and perspectives from those who have contributed to this thread and its offspring. Thanks to all who have participated. I do have a few questions, so, if anyone has answers, I'm all ears. From: "Encore Pianos" <encorepianos at metrocast.net> (Will Truitt) Date: February 7, 2011 11:04:13 AM EST The barrel system to mount the heads is easier to adjust than the blocks, which is why so many manufacturers use it these days. To Will (or anyone else with an answer): Why are the barrel mounts easier to adjust than the blocks? It seems to me that they both allow only one axis of rotation and one axis of travel (the same axis), with everything else needing to be done with wire bends. Maybe you are referring to the gluing on of the new damper, which might require less preparatory wire bends (since the round head doesn't need to be squared to the strings), but once the new damper is glued on, isn't the adjustment process very similar? I think maybe I'm missing something here.... --- And, to anyone who does lots of upright damper work, when replacing/beefing up an older upright damper system for more efficient damping: 1) Is there an optimum configuration of trichord wedge dampers, trichord wedge and flat combination dampers, and double flat dampers (I am grouping butterfly-style flats with plain flats)? At approximately what note going up the scale do you switch from one configuration to another? 2) In choosing between single butterfly-style felts versus double butterfly-style felts versus true flats, what has been your experience and preference as for efficiency of damping? 3) What are optimal lengths for the dampers in each section? For instance, the low tenor starts with damper heads/felts with a total length of _____mm, tapering to _____mm at the tenor/treble break, etc.... 4) Is there any optimal ratio for the length of each piece of felt in a paired damper versus the space between the two pieces? I don't have any clearcut guidelines for making these decisions (which is why I'm asking). I have thus far either duplicated what is there, or, if that seemed parsimonious, beefed things up a bit to resemble what I typically see on more modern pianos. But thats pretty nebulous, and if anyone has more concrete and results-proven guidelines, I would appreciate hearing about them. Thanks, Joe DeFazio Pittsburgh -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20110210/033f5374/attachment.htm>
This PTG archive page provided courtesy of Moy Piano Service, LLC