Paul -
While I had fun running my little experiments yesterday, in shop humidity that was quite a bit lower than today, the information is relatively meaningless, and, to be clear, ultimately of less real value than Fred's humidity data charts, collected over a period of years. The various discussions that have occurred on these lists recently, with regard to action pinning and friction suggest to me a series of dualities (my 'go-to' description for most complexity, thanks to DA) in that any meaningful, coherent discussion entails a great deal of precision, in both implements and process, and yet, unless falling outside the rather broad range of spec-tolerance that real-world conditions and materials impose, such discussion becomes relatively irrelevant.
Within those fairly large, real-world tolerances, on any particular day, frictional anomalies would seem to have more impact on our actual testing, or key weigh-off (using traditional downweight-upweight assessment) than the actual functioning of the instrument. Balance weight, action ration and consistency of regulation/voicing seem much more significant.
I would offer some of my own experience, with regard to the need for one, or both of the Correx gram resistance gauges that Pianotek offers (which I don't have) as well as the set of 4 P.K. Neuses spring steel gauges (which I do own), however, I'm somewhat leary of doing so, where the decision seems ultimately not up to you but the Dean. This would suggest a completely different thread, on CAUT, with regard to how your department is organized and the range of discretion you have in what you do.
That said, I believe that we should have the best, most reliable measurement tools we can find, even if for the main purpose of calibrating our less precise devices. It will always be a matter of balancing cost and faith: my $180 digital psychrometer is supposed to be accurate to +/- 2%, but certification would have cost about twice as much. I would love to own the Correx gauges (both of them) I doubt the Correx gauges would provide measurements radically different from what I get from the two (of the 4) Neuses gauges that I've used, for years - 0-10 grams and 0-30 grams, but I'd love to own them, to be able to confirm.
In the short term, there's the ol' swing test, which will show you the out-liers. Here's what I do with an assembled action. If it's already common technique, I apologize:
- remove top action (I seem to remember that Bill Garlick hated the term 'stack')
- remove repetitions #'s 1 & 88
- use action cradle (Pianotek #ACC-1 or Schaff #296) to suspend action. Clamp firmly but not stressing brackets to risk cracking
- rotate action to allow hammers to swing freely.
- block repetitions (between let-off buttos and jack toe) to prevent swinging hammer from hitting rep
- count swings of each hammer (making sure there's no interference with adjacent hammers). Number of swings is usually one less than same test conducted with part dismounted.
- spot check (dismount and measure) the friction of X number of swings. This should give you a good assessment of any problems, without having to dismount and measure each one.
- with a little finessing, method works well for reps too.
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David Skolnik
Hastings-on-Hudson NY
914-231-7565
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Original Message:
Sent: 09-05-2014 07:55
From: Paul Williams
Subject: Steinway pre-hungs re-visited
Thanks David.
This is good information to store in my rebuilding file until I get a gauge. The good one from Pianotek is pretty spend though. I'll have to ask the Dean.
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Paul T. Williams RPT
Director of Piano Services
School of Music
813 Assembly St
University of South Carolina
Columbia, SC 29208
pwilliams@mozart.sc.edu
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Original Message:
Sent: 09-04-2014 16:50
From: David Skolnik
Subject: Steinway pre-hungs re-visited
Paul -
I also wrote to Kent, who graciously cc'd me the response he provided you with. While he was fine with you (me, or anyone) posting it to the list, I thought I'd hold off for a bit, so as not to go too far afield from your original thread. I did feel inspired to do a somewhat unscientific test, as I happened to be in the midst of a repinning job now. The method of observation does not take into account any sideward oscillation that might affect the actual data, but it's probably as accurate as Fred's humidity readings:
Steinway M
Hammer #1 = 11.3 grams strike weight
0 gr friction = 282 swings
1 gr = 22 swings
2 gr = 16 swings
3<4 gr = 10 swings
4 gr = 7 swings
Hammer #88 = 6.2 grams strike weight
0 gr friction = 282 swings
2 gr = 18 swings
3-4 gr = 6 swings
11.3 grams put #1 hammer right in the middle of Stanwood's medium zone. I added 2 grams to hammer mass and re-tested at 1 gram friction and got 22ish swings.
I'd say that the swing test will still get you pretty darn close if you initially correlate a few sample measurements (swings to gram readings). Gauge is thoroughly useful.
Still room for the theoretical aspects, at some point
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David Skolnik
Hastings-on-Hudson NY
914-231-7565
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Original Message:
Sent: 09-04-2014 10:57
From: Paul Williams
Subject: Steinway pre-hungs re-visited
Yes, I should have stated the piano is getting reconditioned rather than rebuilt. Thanks for the clarification Larry.
I emailed both Ben and Kent. They said that #1, I should get a gram resistance gage rather than the swing test, so that's now on order. #2, the 7-9 swings might be a standard for other makes and/or more like what Steinway did years ago even before the teflon era, but are standard to be a bit more free nowadays. Am I thinking the 7-9 is for uprights? I may have mixed my swings!
I will go with their advice and see how it comes out with the freer pinning. Now, on to the traveling and straightening the hammers. Not too much of that. Much better than the last time I did this 3 years ago.
Tune on!
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Paul T. Williams RPT
Director of Piano Services
School of Music
813 Assembly St
University of South Carolina
Columbia, SC 29208
pwilliams@mozart.sc.edu
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Original Message:
Sent: 09-04-2014 08:37
From: Larry Messerly
Subject: Steinway pre-hungs re-visited
One can see definition of rebuilding and reconditioning in the council book of resolutions.
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Larry Messerly, RPT
Bringing Harmony to Homes
www.prescottpiano.com
larry@prescottpiano.com
928-445-3888
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