How unparallel are you talking about? If the hammer is radically non perpendicular to the string then it will be striking askew and not on the strike point. That might stress the glue joint as the force would be taken at the joint rather than straight through the hammer moulding. The voicing would be another issue. But if the hammer is perpendicular to the string at contact then I don't think it makes much difference as to whether that shank is parallel to the string or not. There are many examples of pianos (older Bechsteins come to mind) that are short bored and the hammers are raked out. It may cause a slight raising of the let-off button and drop screw. But I haven't run into one that couldn't be regulated. You can even argue that with the hammer shank starting in a higher position it minimizes the change from a horizontal to a vertical vector (do I have that right) and the action will actually weigh off slightly lighter due to a reduction in friction. You can even make the argument that since shanks tend to flex on the way up, that slight short boring without the rake is justified since that will likely result in the hammer hitting perpendicular to the string. For those reasons, if you are going to err, err on the side of short bore as opposed to long bore. Though I always aim for the hammers perpendicular to the string at impact, minor variations are not likely to cause a great deal of trouble. As far as shank parallel to strings, it's a reasonable standard that usually allows everything else to fall in line. But in and of itself, much ado about nothing. David Love davidlovepianos@earthlink.net > [Original Message] > From: Phillip Ford <fordpiano@earthlink.net> > To: <pianotech@ptg.org> > Date: 6/16/2004 2:44:20 PM > Subject: Shanks parallel to strings > > I would like to revisit the idea that shanks should be parallel to strings at hammer contact. I know we've had some discussion of this before. I looked back through the archives and also in the back issues of the Journal and couldn't really find what I wanted. I would like to have some theoretical reasons why having the shank parallel to the string gives better action performance than not having it parallel. The standard thinking seems to be that the hammer should be perpendicular to the string line at contact and the hammer should be perpendicular to the shank, which results in shanks parallel to strings. I can see reasons for having the hammer strike perpendicular to the string line. But I don't see any good reason for having the hammer perpendicular to the shank or the shank parallel to the string. Reasons given in the archives or the journal for not permitting non-parallel shanks are along the lines of: > > 1. It's bad practice. > 2. It reduces power delivery. > 3. It won't give as strong a joint at the hammer to shank interface. > 4. The regulation will get screwed up. > > As to these reasons: > > 1. If it's bad practice, is there some explanation on offer? > 2. Why would it reduce power delivery? The hammer is still traveling in the same path as it was before - the angle of shank to hammer doesn't affect that. If the hammer is still striking perpendicular to the string why would any reduction in power have occurred? > 3. I don't see that the joint should be weaker. If anything, having the shank not perpendicular to the hammer would mean that the hole through the hammer has to be a little longer, which would seem to result in a stronger glue joint. > 4. I can see that this would be true if the action was designed to work with the shank parallel at contact, and that drastically changing this would cause various things like rest rails and letoff buttons to be in the wrong places for the new shank position. But I'm talking about an action that was specifically designed to have the shank non-parallel at contact. In this case everything could be positioned to work properly so that regulation would not be compromised. > > Any thoughts? > > Phil > > > > Phillip Ford > Piano Service and Restoration > San Francisco, CA > _______________________________________________ > pianotech list info: https://www.moypiano.com/resources/#archives
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