Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Baldwin capo: a metallic-buzz sound generating system

I have a Baldwin with one of those hard, nasty, metallic sound generating systems in the capo. Like the string, I'm over it. I know I could put in upside-down agraffes, but I'd rather not take everything completely apart...

I'd like to remove what is there, level/polish the metal flat, and then install a brass or iron V bar. Anything would be better than the racket that goes on in the piano now--which not even a fully muted duplex can begin to tame.

I have seen this approach on both new and old pianos (i.e., not on Baldwin), so I know that it is possible. However, there are many technicians that state this kind of metal to metal solution never works. Before I attempt something like this, I'd like to know why? What are the possible things that could go wrong? I assume if I am using two perfectly flat surfaces, and the bar is soft enough (i.e., not a hard metal that rings/vibrates), this should be straight forward. No?

.... Can you be a little more specific as to the year and model of Baldwin?

I think Ed McM has presented you with lots of useful tidbits in v-bar profiling etc. Del may have a thought or two as well. Such a role reversal...

I have just taken in a Baldwin SF-10 that has the (terminal to tone), treble termination inserts. I have not yet come to a complete plan. I am investigating cutting out the existing capo bar and having cast a piece that I can machine into a bolt in capo with upside down agraffes for the treble.

Sounds like a pain in the kazoo Ed. I often wondered how wonderful those inserts were. These are the ones just prior to the hitch as memory serves. They were intended to be moveable, were they not? Sort of a more sophisticated tunable duplex as I recall. Or are you meaning something on the capo itself?

But, Ed McMorrow, RPT, why go thorough all that? Is it to get that last bit of perfection? Or have you tried to polish the iron flat and use a soft well-fit metal to create the V-contact point (i.e., and it somehow sounded horrible)?!? I know some have tried this and failed by either using too hard a metal, and/or not having gone through the levelling/polishing process to ensure a good fit. I'm just wondering if there is something that I am missing. What else could go wrong...that I may not be thinking of?

...if it is for perfection, that part I get. But, if you've already tried something similar to what I am talking about and already eliminated it from possibility for yourself because it sounded somehow strange/odd<---that is something that I'd like to know!

SMHaley,
The inserts are bolted between the capo bar and the tuning pin area and have a radius on a hard metal flange that the strings pass over.

A443,
I am not absolutely clear on what you are proposing to comment directly. I have also not been able to spend the three days it will take to mark up and lay out all the things I want to fix on the SF-10-so it will be a while till I can report what I am going to do. And I might decline the job if I discover some problem. The scale of the SF-10 is weird-and I have to see if I can get everything into proper balance. The piano does have an excellent board. This is my first one SF-10.

As regards capos, the principle is that the termination must be softer than piano wire so the string can self-machine the exact shape that works best-and the pivot termination must be maximized. For that you need my Fully Tempered Duplex Scale which does require a modest license fee to me.

Maybe you could try hollowing a groove and place a phosphor bronze rod there. The Pb is slightly softer than music wire and harder than brass.

I doubt any brass/bronze rod that small will hold up well to the bearing.

Oh, yes. I recall that now. Confusing it with "aliquot" hardware...eeek.

I know techs that have used it for years with no problems. 3 years so far on my vertical looks brand new with no grooves that I can see.
I never said what size rod- Did you think 1/16th? I believe the size I used was between 1/8- 3/16".

When i build my 7'6" grand. I am going to use rolled steel and I plan on using the phospher bronze, so I back up my advice.

I was curious what D. Rubinstein did? Rolled steel and music wire could be a potential buzz/ breakage problem.

My plan was to remove the noise maker (i.e., whatever it is called), polish the iron capo flat, and set in a metal termination piece (i.e., either individual for each string, or one long bar--depending on what I can find) between the iron capo and the strings.

I dont know what you want to do but bronze berylium rod is good for inserting , to repair a worn capo or replace a similar rod done in steel.it may hold only with string pressure, once fixe at each end wirg 2 pins

machining the channel or the flat to put it on is the difficult part

From my work with optimizing pivot termination-1/8" would be too much string contact area. Smaller diameters would have the requisite full pivot, but not be strong enough to hold up.

How much does the change in downbearing need to be compensated for?

I'll take a picture; or maybe a video is better. You may not be familiar with this particular Baldwin contraption in France--I don't know. There are zero string grooves in the metal: the capo is in perfect condition!!! Yet, it is the buzziest piano I've had the displeasure of being around (i.e., which more-or-less proves to me that string grooves in capos are not the source of capo buzzing problems). It's really a disgusting sound, but the pianist likes the touch/feel of the keyboard--and there is some sentimental attachment--so it's not going anywhere.

I really don't want to take the plate out because of the situation, which is why I am not into the machining strategies. If I can get the contraption out, I know how to polish that part of the capo and the insert perfectly flat. I'm just concerned that the metal insert(s) might rotate forward ever so slightly (i.e., like the bridge of a violin) and either buzz or create an odd loose of energy with the lack of complete contact--or maybe with the bearing, this is not even an issue. I think I have experienced the later on the piano before, but I never had the opportunity to investigate further.

Baldwin SF7 in my tuning clientele...



Horrible front string noise due to these counterbearing mechanisms. Sheer guesswork as to how to tune the upper treble. I'm never quite sure that I've left the string stable. The customer did say to me that I'm the only one who's tuned it that could get a tuning to last, which made me feel good. I felt like I was pounding the snot out of it to achieve stability.



Plus as an added bonus, tuning pins laid out in such a way that I'm guaranteed not to be able to tune (second-to-last trichord before the strut). Also notice how the scaling repeats sizes 16.5 and 16.

Chris Storch, thank you for the pictures!

The Baldwin is what convinced me that there are some pianos that must be brutally beaten during the tuning process. I understand some technicians believe they have great tuning technique that will solve all tuning problems--where banging it not necessary--but not with pianos like these! It is not possible. If it is, I would happily pay good money to see it happen.

I have never really been able to put a respectable tuning on this Baldwin: I'd need to decrease the side bearing at the bridge, install a pin-block that is more wood than glue, and then replace the buzzinator, in order to do that.

A443,
You might investigate whether the terminator can be machined to install an up-side down agraffe. Even if there is not enough material for threads if the hole is sized properly the agraffe could be a force fit. The shank on the agraffe could be reduced if needed.

If this works, I would also remove the duplex rest from the terminator and buy a license from me for a Fully Tempered Duplex Scale. I could provide you with the duplex rest materials and the positioning information.