Last week I regulated a Baldwin R baby grand, vintage 1950, which featured five interesting points in an apparently standard-issue regulation.
1. Hidden studs, including the two outside ones – first time I’ve seen this particular configuration. Unlike the Asian variety, pre-set to neutrally position the balancerail height in a flexible keyframe, these were not pre-set but needed to be adjusted to bed the balancerail. To provide access, I removed five sharps and, apart from the annoyance of two extra topstack removals, this system worked really well. Keystep bedding samples brought the action out to bench easily and no adjustments were needed to the regulating done there back in the piano.
2. The backrail’s underside lip, a common design feature to facilitate factory bedding, was on the inside instead of the outside of the backrail – important to be aware of when testing backrail bedding through strings and action because of the possibility of a false positive creating unnecessary extra work.
3. Hammer spacing in the bass required tilting. I prefer traveling shanks to vertical and squaring hammers to vertical at strike. This has benefits of strongest address, simplest bounce, and least stress on centers, plus a string-to-hammer mating that does not change with soft pedaling.
But this piano insisted on tilting hammers in the bass. Whenever hammers are flared, because of their shape and their arcing path, tilting them on their shanks (unsquaring them a little in the direction of the rear shoulder) splits the difference between rest and strike, maximizing clearance. I don’t like this because, apart from causing crown filing or string leveling compromises to achieve string mating, it amplifies the rear shoulder’s drag on hammer travel. The rear shoulder, being further from the shank’s center pin than the near shoulder, effectively weighs more, travels further, and accelerates more. Tilting in the direction of this heavier shoulder improves clearance but complicates travel, bounce, and tone, issues I prefer to avoid by going vertical.
Usually, it is flare angle that forces a tilt. Clearly, the more flare the more space is needed. Or extra hammer width can contribute as wider hammers need more space. Here, bass flare was moderate and hammers a little wide. Squaring to vertical worked fine in the tenor, with similar degree of flare, spacing, and hammer width. The longer bore distance in the bass was certainly part of why the tenor cleared but the bass was pinched. But offset between hammer and string spacing scales was the clincher. The bass strings along their strike line were to the treble of keys/whippens/hammers, a situation made worse by filing the hammers to a shorter length. This Baldwin was designed to have bass hammers tilted, period.
I looked at the role of travel in this puzzle. Since I had already traveled the hammers vertically, I re-traveled a couple so that travel took crown to strings instead of spacing. The hammers severely rubbed their treble-side neighbors. Not helpful.
Imagine tilting shanks without hammers 90 degrees. Spacing to the neighboring shank would be the shank’s range of motion. Untilt back to vertical and you can see the range extend until going too far would start to reduce it again. While we’re at this, imagine tilting hammers 90 degrees on their shanks. You’d have a full range of motion but each hammer would have to be a full hammer’s length plus a little from the next. You would clearly feel the drag of hammer during stroke suggested by tilting. And hammer-string fit? Back these off toward vertical and both aspects begin to recover until weight and fit simplicity is maximized at vertical – but, in this case, with lack of clearance because of the offset.
An addendum to this point. All aspects of piano design, regulation, and performance involve compromise. The best instruments, exhibiting the best balance of these, involve a very long list of design choices. The product we receive to work on can often be improved to benefit goals of owner or player but its design will limit what can be achieved. I think, however, we can be pragmatists in two directions at the same time, modifying what can be changed for benefit and yielding to what cannot.
4. This action, with 17mm knuckle-to-center distance, actually provides comfortable aftertouch with a normal 1 3/4” blow distance and only a 3/8” dip. Whippen and key lever arms must provide the needed range of motion. Mathematicians?
5. The keys are pattern-leaded to provide approximately consistent downweight, a style more often found in Europe and Asia. With the loss of hammer weight to filing, only one note was upweight deficient, easily solved without a full weighoff.
This customer has 40 students and she, at a gray-haired age, studies to improve her performing qualifications. The cost of this work represents a large investment in long-range benefits to herself and her students. On the morning before installation, starting to adjust dip to regulate aftertouch, I realized that the 1/2” sharp height I had replicated was unnecessarily high (and would be forever if I left it that way). With adequate balance keypin above button and plenty of front keypin in mortise, I added a yellow and a blue balance punching (.022” total) to each natural.
I should have done full regulation samples right away once I was set up on the bench. But I felt time-challenged and calculated that there was plenty of leeway. Well, there was plenty of leeway and, in fact, too much enough to add extra, unnecessary work for a player's fingers. So, I made a not-too-expensive modification that would have been my bad to leave out.
But I don’t think I would have believed the sampling results anyway. A naturally occurring 3/8” dip!
Thanks for the comment Ferdinand. You’re right, I was unclear – I was referring to the thicker yellow (.012”) plus a blue (.010”), rendering .022” at the balance and about .044” at the front, making the sharps a little more than 1/32” shorter for the player. Considering the natural dip of only 3/8”, this made the action so much more comfortable to play.
One yellow and one blue punching would yield .012 change in height at the balance rail. That may translate to .022 at the front of your particular action, but it was just stated in an unclear way. That would not be true on keys of a different ratio. In general if the balance rail is truly at one half the key length, then added a punching will double its height at the front of the key.
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