This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. ---------------------- multipart/alternative attachment Chris, =20 My string heights are in the 7 1/2" range for the most part (a little = higher in the middle) and the hammerflange centers are at 5 =BE" so the real = problem is getting the 1 =BE" blow distance without peeling the bumper felt off = to within 1/8" of the wood. I've dealt with a couple of actions where I = would like to raise the rear of the stack up to avoid the "dreaded repetition lock-up" but have glued extra felt on the bumpers for the sake of expediency. Do they ever actually induce warping in the stack at the = factory to match the curvature of the string heights? I've never had a stack = that rocked on a flat bench or noticed one that was flexed into a curve on = the keyframe. =20 Eric =20 Eric Wolfley, RPT Supervising Piano Technician College-Conservatory of Music University of Cincinnati =20 -----Original Message----- From: Chris Solliday [mailto:solliday@ptd.net]=20 Sent: Wednesday, July 20, 2005 12:52 PM To: College and University Technicians Subject: Re: [CAUT] Steinway stack height =20 Eric, the real relationship in this is of course from the string to the center heights. If 7 1/2" is the string height, correspondingly the = hammer center height should be 5 3/4" which is a difference of 1 3/4" ( a = familiar number), so consequently shouldn't the hammer center height be 5 1/2" = if the string height is 7 1/4" ? Is this what Mike Mohr means by "the action = height is unique..." and "Maintaining the relationship between... ?" Just a = slight caution regarding lowering the stack height only in the back, it can = result in the dreaded "repetition lock-up." But with your shanks so close to = the cushions it's probably not a problem. I think Pianotek sells different = size rest felts so you can maintain a good relationship to the shank. As for = the straightedge thing it doesn't mean that you should just stand there = forever checking it continuously, however great a relief from our regular = duites this may be, but rather just when setting the two center mounting = blocks and maintaining a slight curve (or not) to match the string heights. = Although it certainly would be a good way to measure warping if you knew where it = had originally been set. Accurate string height measurements are really = key, especially with Steinways, for this kind of work. Chris ----- Original Message -----=20 From: Wolfley, Eric <mailto:WOLFLEEL@UCMAIL.UC.EDU> (wolfleel)=20 To: 'College and University <mailto:caut@ptg.org> Technicians'=20 Sent: Thursday, July 21, 2005 11:29 AM Subject: RE: [CAUT] Steinway stack height =20 Thanks Chris and all that replied. I'll thumbtack the specs to the wall = so I won't misplace them. I did contact Kent Webb and the current spread specification is 4 13/32" which translates to 4.40625" =20 The piano in question is indeed of 1968 vintage (Mr. Purdy) and was originally Teflon with the big fiber knuckles. I isolated the problem = to two sources: The rear of the stack was 1/16" too high (3 5/16")...easy = enough, I carefully planed the shoes down. The shank bumpers on the new wippens I = want to use (Tokiwa miracle wipps) are 1/8" higher than the original. We = save a lot of old parts here...it was good to have some samples to check. This piano had a new soundboard installed a few years ago (before I started = here) and obviously the string heights are lower now than its original incarnation.=20 =20 In Chris's post below I can't exactly visualize what they are talking = about when they say "continually check for straightness with the straightedge = on top of the hammershank flanges". My only guess is that if the mounting blocks aren't all on the same plane the hammer rail could warp down or = up where a stack bracket is screwed down but it seems like it would have = to be really bad for this to happen. =20 =20 =20 Eric Wolfley, RPT Supervising Piano Technician College-Conservatory of Music University of Cincinnati =20 -----Original Message----- From: Chris Solliday [mailto:solliday@ptd.net]=20 Sent: Monday, July 18, 2005 5:07 PM To: College and University Technicians Subject: Re: [CAUT] Steinway stack height =20 "B" at note 62 in NYC hammer flange 5 3/4" rep flange 3 1/4" based on string height of 7 1/2" you didn't say = if pre 84 or post or the new incarnation but the spread pre 84 was 4.381" and = post 84 was 4.395" This may have changed on the latest and greatest and for = that I suggest you call Kent Webb or email him. I think it is important to = note that according to Mike Mohr's Forefinishing Notes, which I consider a reliable source, "Set Action Frame Height" says "IMPORTANT NOTE: the = action stack height, as determined by the thickness of the mounting blocks. = This action height is unique for each instrument, and is the result of the individual string height for a piano. String height variables are the = result of the plate fitting and belly operations... String heights change from = bass to treble usually in an arched or crowned manner. These numbers for = note # 62 represent an average. Maintaining the relationship between the stack height and the string height ensures: A) the proper BLOW distance at = the same time the hammershank is properly off the cushion. and B) the = proper HAMMER ROTATION is needed to minimize overstriking or shallow striking conditon. NOTE; if string height is lower or higher than above, keep = the relationship the same..." (and later after shimming or planing the bass = and treble mounting blocks) "continually check for straightness with the straightedge on top of the hammershank flanges." I know you only asked = for numbers, but what the heck, I felt like sharing. BTW I'm sure you = remember that we discovered when shimming or planning it is best to rotate the = stack on the hammer flange pin axis which means adjusting the front foot differently than the back foot. Of course there are even greater = subtleties to this process but then you did just ask for the numbers. Stay well, = Chris Solliday =20 ----- Original Message -----=20 From: Wolfley, Eric (wolfleel) <mailto:WOLFLEEL@UCMAIL.UC.EDU> =20 To: 'caut@ptg.org' <mailto:'caut@ptg.org'> =20 Sent: Tuesday, July 19, 2005 9:53 AM Subject: [CAUT] Steinway stack height =20 Hi All, =20 I'm sure somebody out there knows the specs for the distance from the = keybed to hammerflange center and keybed to wippen center for a Steinway B. I = have these written down somewhere but can't find them and I don't trust my memory. I'm correcting a problematic action and believe the stack to be = too high since to get the proper blow distance the shank cushions have been reduced to nubs. The bore distance of the hammers is correct and the = string heights are in the normal range. =20 Thanks! =20 Eric Wolfley, RPT Supervising Piano Technician College-Conservatory of Music University of Cincinnati =20 ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/caut.php/attachments/08/96/2f/50/attachment.htm ---------------------- multipart/alternative attachment--
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