---------------------- multipart/alternative attachment >At 6:43 PM +1100 11/30/01, Overs Pianos wrote: > >>. . . . During the early 1900s actions were set up typically with >>hammer/key ratios between 7 - 8:1. . . . > >Let's get this clear. Are you saying that 1900+ pianos could raise >the nose of the hammer vertically 45 mm with a vertical key dip of >5.63 - 6.43 mm and that if we allow an _arbitrary_ 1.5 mm for full >escapement we can set the touch depth on such pianos as low as 7 or >8 millimetres?! That's the only inference I can draw from your >statement You may well, but I haven't actually tested the inference you've drawn since I haven't made an in depth assessment of every action we've have worked on. I am more interested in pushing the limits of the modern action, in particular the one I designed in 1999. >so . . I am misunderstanding your ratio or you need to change the statement. The statement I made is based on what we have actually measured in the various pianos we have rebuilt - and yes we do record the data on a spreadsheet for future reference. You can take it or leave it. >>For example; >> >>Steinway 1906 model 0 >>183/217 x 95/67 x 138/20 = 8.25 > >The 1906 Steinway O that I have . . gives > >Lever centre to scribed line: 93.5 >Lever centre to capstan contact: 67 >Hammer centre to jack contact: ca 22 >Hammer centre to hammer nose: 138.2 >Key front lever (balance to ivory corner): 233 >Key back lever (balance to capstan/lever heel contact: 125 > >According to your method of reckoning that would give, for two >different values of the roller arc: > >125/233 x 93.5/67 x 138.2/22 = 4.70 You won't get the figure of 22 from hammer centre to jack/roller contact on an early action, since a dimension of this size is only possible with a large diameter roller with at least a 17 mm roller slot to hammer centre distance. >125/233 x 93.5/67 x 138.2/20 = 5.17 Unless the figures you posted were taken from an action with the wrong spread distance, there is something wrong with the figures - see small diagram included in the link below on calculating the ratio. If the spread is correctly set at 112.5 mm, the sum of the two figures for jack/roller to hammer centre, and jack/roller to wippen centre will be very close to 114.5 mm. (Image link below shows measurement points for determining hammer/key ratio) http://overspianos.com.au/anrt.html Hammer key ratio = (B/A)*(D/C)*(F/E) You measure the first key lever length from the 'ivory corner' (as did Dr Pfeiffer). We measure from the top of the key top at the intersection of a line through the front pin. This will cause a further disparity between our calculations. I choose this position as the point of reference for measuring the front lever, since most pianists do not play with their fingers positioned on the front edge of the key. As you yourself previously posted, most pianists will play with their fingers positioned well away from the front of the key. This variation of measurement points will give you a slightly lower measurement than we get. Have you measured a number of pianos and recorded the data, or have you measured the one model O, concluding that others of the period would all be the same? The example I provided was just one example of an early 1900s small Steinway, and yes we have other similar figures from many instruments of that period. Clearly the figures you posted are quite different. These actions would appear to be completely different designs (the key dimensions are certainly very different). Nevertheless, the trends which I wrote about do exist. I've measured enough piano actions to be confident in drawing such a conclusion. When considering the careless application of design standards which was commonplace during the early 1900s including S&S, who claim never to put a foot wrong, it is not surprising to find extreme variations from the normal trend. >(Key ratio 100:186) The key ratio is one action design factor which, when considered on its own, is completely irrelevant to action geometry (David Stanwood also, has posted a similar statement previously). It is the overall average of the hammer/key ratio which is critical to action performance, of which the key ratio is only a one-third part. >>This change of the hammer/key ratio from higher formerly to the >>modern lower figure is precisely why you cannot fit a modern denser >>and heavier hammer set to an older piano with a higher ratio, ie. >>unless you are prepared to move the capstan position and the >>knuckle slot to revise the ratio back to what will be required for >>proper function. > >I always fit the lighter hammers and a 9 mm. roller. Which is in agreement with what I posted. >Is it your experience that you can make enough difference by >altering the geometry as above to accommodate the 'standard' modern >Steinway hammer without significant overleading? Yes. An excess of lead is a sign of a poor match of hammer weight to hammer/key leverage ratio. >One would need to prefer the sound of the heavy hammers an awful lot >to go to this bother, and I don't in this case. One would, but some clients do. So what do we do, tell them they're wrong? I don't care which way they want to go. If they're happy with the thinner tone of a standard weight smaller hammer, that's fine and it'll be cheaper. If they want the bigger tone that will require a heavier more modern style of hammer, that's fine too. But it will cost them more since we'll have to reset the capstan and heel position and possibly the knuckle location as well. However, it is less desirable to set the knuckle further away from the hammer centre, because it will make an already poor jack tail to let-off relationship even worse. >On a slightly related issue, you might be interested to know that I >bought an 1899 6'6" Lipp grand the other day at auction -- never >touched, not tuned for 40 years, beautiful! I pulled out the works >expecting to find a Keller action with the spiral repetition spring >but was delighted to find our old friend the short lever Herrburger >action, probably in its first incarnation. The knuckle is special >and the jack tails are covered in doeskin but the lever is >essentially the same as that they used up to 1914. I'll take a >picture and let you have it. I look forward to receiving it. >The 'related issue' is that Lipp grands have a wonderfully free >action but it tends to be too light for most professionals. I have >had great success in the past fitting heavier hammers to these >pianos. This not only makes the touch more manageable but adds >fullness to the tone. Exactly. As you mentioned earlier, it is an awful lot of bother to reset a leverage ratio to install a heavier set of hammers. Its the old story all over again, we always need to determine if the bother is worth the gain in everything we ever do. Getting back to your Lipp action, you mentioned that with 'a wonderfully free action' you can fit a heavier hammer set to gain fullness of tone. In the case of a reduced friction action, gaining a fuller tone with a heavier hammer set is not much bother at all. Ron O -- Overs Pianos Sydney Australia ________________________ Web site: http://www.overspianos.com.au Email: mailto:ron@overspianos.com.au ________________________ ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/8f/1b/32/da/attachment.htm ---------------------- multipart/alternative attachment--
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