The only issue with the longer bore and thinned rest cushions that I can think of is if the shanks contact the balancier regulating screws on a hard rebound. The touchweight dynamics can be influenced by the shank starting at a lower angle. The increased travel along the horizontal axis can increase the force required to initiate the key stroke when compared to a higher starting point. David Love www.davidlovepianos.com -----Original Message----- From: Mark Cramer <cramer at brandonu.ca> Date: Wed, 02 Jun 2010 10:00:16 To: <caut at ptg.org> Subject: Re: [CAUT] Steinway extra-bore-length Okay, that's a rationale I can live with. In this case however, with *thin* rest cushions I actually *can* bore the hammers to full length (51mm, if memory serves) and still move the action in /out without angling (pitch) the hammers. BTW, regarding stack height, maybe I wasn't clear enough... I have NO intention of tampering with this. There is simply no need. What I should've asked perhaps is what good reason is there for *not* lengthening the bore when it will solve a strike issue, especially when case fit isn't a problem? Steinway obviously couldn't do this being limited to their stock bore lengths, and I wouldn't either, from a manufacturer's point of view. This particular supplier however had strong opinions about extra bore-length affecting the performance of the action. I don't get it, and would appreciate someone enlightening me as to why, if in fact it is an issue. Strike-weight wouldn't be that big an issue. Otherwise, I'm planning to go back to the 51mm bore, and my only caution to others calculating a bore-length longer than stock, is make sure it all fits back in the piano. thanks, Mark Cramer, Brandon University PS I have no issue whatsoever with a blow-distance that results in bass hammers rubbing the pin-block going in and out of the case. All performance objectives considered. On 02/06/2010 9:02 AM, David Love wrote: > > So the standard bore of 1 15/16" in the tenor treble increased to 2 > 1/16" was the difference between being able to get the hammers under > the block? If that's the case then practicality reigns supreme. Use > the maximum bore that still allows the hammers under the block and > angle the hammers back to get them at 90 degrees at string contact. > There are many examples of pianos that do this without any problems > and an extra 1/8" of travel requires a minimal angling especially when > combined with the upward slope of the strings from termination to bridge. > > David Love > > www.davidlovepianos.com > > *From:* caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] *On Behalf > Of *Mark Cramer > *Sent:* Tuesday, June 01, 2010 8:43 PM > *To:* caut at ptg.org > *Subject:* [CAUT] Steinway extra-bore-length > > A week or so back, Jon Page mentioned the correct method of > calculating hammer-bore length. > > Thanks for that Jon, it's the same method we use, excepting where the > hammers are deliberately pitched, but here's a funny story from a few > years... okay, a decade ago: > > I was preparing hammers for a 1980's D and found that bore length > worked out about 3mm (1/8th) longer than spec. Since we tend to buy > our hammers un-trimmed and extra-length, it was no problem to bore > them with plenty of tail length. As a caution, I tested samples on the > bench and all was fine. Fine... until installing the action that is. > > The action wouldn't fit back in the piano... even with the shanks > buried in the cushions, no deal! (that was the chuckle part, the rest > is pretty boring, but I do have a question) > > So, we thinned the cushions and even shortened the balancier height > adjustment screws. All worked wonderfully, and /three years later/ I > repeated the dimensions with the next set of hammers. / > > Three years later again/, I was pressed for time and ordered some > pre-hung aftermarket hammers. The supplier was quite adamant that the > hammers be bored to original spec, even though this would result in > over-strike. Knowing I had room to push the action back (return to > factory position), I went along with their advice, even though it > meant replacing cushions, etc. > > Now it is /"three years later" yet again/, and time for fresh hammers. > > I really like the idea of the hammers being at right angles to the > string, and the shanks horizontal at strike, which is the result we > get with Jon's measurements. However, I wonder about the implications > of the extra-long bore... aside from the need to get the action in and > out of the piano that is. > > Raising the stack (3mm) would take care of things, but this is really > a very efficient action, and I neither want, nor see a need to tamper > with that. What's more, I can't say I really noticed a difference in > performance with either bore dimension. > > The Question: > > So, what are the rest of you (and Jon) doing in this situation, and why? > > thanks, > Mark Cramer, RPT > Brandon University > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/caut.php/attachments/20100602/4a8b2f7d/attachment-0001.htm>
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