Rolland Miller wrote: > > Hello list. > > A big "Thank you" to all who responded to my request for help. > > I "diagnosed" the piano today and it had a 1st in it for me - bare felt > knuckles - no buckskin. The knuckles were about 13/16" in diameter. 13/16" is > the diameter of a Steinway knuckle (with buckskin) I have in my shop. I called > Steinway about it and the technician that I talked to had not heard of a > Steinway with bare felt knuckles. He said he would mention it to Mike Mohr and > Mike would get back to me after he got back from vacation. My customer said > that he believes all the parts are original. He has owned the piano since it > was new. > > Back to the action. > Action spread was 4 13/32" at hammers 1 and 88. > I didn't get distance from knuckle to flange pin nor did I get either flange pin > to hammer, or hammer bore. > When setting glides I found that the key frame was not well bedded to the key > bed as the middle of the K frame had good contact and the ends were about 1/32" > above the key bed. I did not try to remedy this problem as this was an attempt > to diagnose? rather than repair. > > Regulation specs after setting glides, > Key height from bottom of key frame to top of white = 2 1/2" > Key dip very close to .390 > Let off was close to 1/16". > Hammer blow was about 1 5/8". > Drop was just a bit low at about 1/4" - the drop screws were turned way down. > Except for the hammer blow distance and drop measurement, these were about the > specs I would aim for myself. > > Testing with the above specs, > I found that the jacks still blocked hard. Way too much after touch - I didn't > bother measuring it. > > Trial and Error, > I found that a key dip of about 5/16" and a hammer blow of about 1 7/8" would > get an after touch of about .060. > On the other hand a key dip of .390 and a hammer blow distance of 2" plus would > get an after touch of about .060. This 2" plus hammer blow won't work though as > the shanks are resting on the rest cushion and the hammer tails would normally > catch on the backchecks. > > If I have to, I think I can get a "working" regulation with a key dip of > slightly less than 3/8" and a hammer travel distance in the 1 7/8" range. I > don't like the specs though and would like to further evaluate the action > geometry to see if I can find a solution that will keep the key dip, hammer > travel and after touch closer to their "design" range. > > Below are the string height measurements in case there is something unusual > with those. > Bass section 7 15/16" and 8" > 2nd section 7 5/8" and 7 21/32" > 3rd section 7 5/8" and 7 9/16" > top section 7 9/16" and 7 1/2" > > Again, any advise, opinions, suggestions or "2 cents worth" will be greatly > appreciated. > Thanks again.!!!! > Rolland Miller, 70642,3604@compuserve.com Rolland, My shop did a lot of Steinway dealer prep work during the 70's. One of the things I learned about them was that there were no standards. Hammer blow came in consistently between 41 mm and 48 mm. (From a shy 1- 5/8” to a proud 1- 7/8”) Key dip, as they arrived from the factory, ranged from about 9 mm to about 11.5 mm. (From a very shy 3/8” to a proud 7/16”). The rest of the regulating specifications were equally reasonable and consistent. For the most part they could be made to work with a hammer blow of 45 mm and a key dip of 10.0 mm. This would usually result in a key aftertouch of approximately 1.5 mm. If we had trouble getting 1.5 mm of key aftertouch, one of two things could be done. First, key travel (i.e., key dip) could be increased. However, 9.5 mm to 10.0 mm seemed to be the limit that pianists found acceptable. If key dip got to 10.5 mm some pianists would complain about excessive key travel. So the second approach became our standard practice. We would shorten the hammer blow until we got 1.5 mm of key aftertouch with 10.0 mm of key travel. The minimum acceptable hammer blow distance was 42 mm—if the hammers are set any higher than this there can be clearance problems between the hammers and the bottom of the pinblock and the stretcher. The downside of this practice was mostly theoretical. In theory, by reducing the hammer blow from 45 mm to 42 mm there should be a slight loss of power. This was never noticeable either to me or to the pianist. Only rarely would we have cause to set hammer blow beyond 45 or 46 mm. The 48 mm to 52 mm plus figures I’m hearing about seem quite excessive to me. Keep in mind that the hammer blow distance and the key travel distance are directly related. If you shorten up on the hammer blow distance, you will also have to reduce the key travel distance (key dip) to maintain the proper amount of aftertouch. The all felt knuckle was an experiment from the late 60’s—I don’t remember exactly when, they had been phased out by the time I started doing this work. It may present some problems, but not the one you’re encountering with binding jacks. They could be a bit noisy and they were often “lubricated” with some pretty horrible stuff which probably contributed even more problems. I suspect that with powdered Teflon they might have worked somewhat better. (Those that I serviced seemed to work fairly well, but I’d really like to hear from others on this subject.) It was a rare action that would not work within these parameters, and then the problem was action spread which had to be dealt with before going on. If I understand your problem correctly, action spread is not a problem. In the discussion that follows I’m assuming that the keys are properly leveled to a height of 67 mm. I’m also assuming that the jacks are properly aligned to the hammershank knuckles and that they have been properly “winked,” that is, that they are correctly aligned to the tops of the repetition levers. If there is a gap between the jack and the hammershank knuckle, it will have the same effect as it has in an upright action. The action will have lost motion and the key will have to travel further to move the hammer through let-off. To make these jack adjustments, of course, the repetition springs will first have to be reasonably well adjusted. In any case, your problem is with binding jacks. Assuming that the rest of the action is reasonably well adjusted, there aren’t a lot of things that can cause this. Some that come to mind are: 1) Excessive key aftertouch. Key aftertouch is our insurance policy against bobbling hammers. After let-off the key no longer controls the hammershank or the hammer. To keep the hammershank knuckle from bouncing against the tip of the jack, the key keeps traveling and rotating the jack until the tip of the jack is just in front of the knuckle. Any rotation of the jack—i.e., any further key travel—is unnecessary. The hammer can now bounce away from the string and go into check without the hammershank knuckle binding against the tip of the jack. In general, key travel after jack let-off should be no more than 1.5 mm, but look at the jack. The criteria is that the tip of the jack must clear the returning hammershank knuckle without binding against the front of the repetition lever mortise. 2) The hammershank knuckle (and the jack) are located too far toward the front of the action (i.e., toward the hammershank rail) reducing the clearance between the jack and the jack stop felt in the repetition lever mortise. 3) The jack stop is either too thick or the mortise in the repetition lever is not cut long enough. In either case the jack would not have enough room to fully escape after tripping out from underneath the hammershank knuckle. I do remember replacing a couple of sets of jack stop felts. 4) Improperly assembled jacks. I have seen this only rarely. I mention it only because we did have to replace one set. I should think that any defective jacks would have been replaced years ago—it was pretty obvious. In the end, I suspect that you’ll find your problem is a combination of things. Start from the beginning and regulate the action—beginning with the keys and working up. Don’t leave out anything. At first—until you have reason to do otherwise—keep the hammer blow at 45 mm and see if you can make the rest of the action work. You may have to set the action up on a bench and stare at it for awhile. I hope the above helps and keep in touch. —ddf
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