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I just wrestled with a Baldwin L which needs restringing, but won't get that for who knows how long. It is around forty years old and has some noisy agraffes and some other metallic jangles (tone leakage) in spots along the upper bridge (capo). The overall job was hammer shaping, regulation, tuning and voicing. It took about 12.5 hours, when I charged for ten.

On to the voicing issue: I did deep needling on the loud notes. Then closer-to-the-crown work where it was needed. Once I got to the final voicing, the judging of the higher partials demanded that I deal first with the noises. I used the tricks I typically try in this situation:
A. On the agraffes, I loosened the string a third and then lifted and deflected the strings to attempt to cut down on the noises - in effect, rolling them around the insides of the agraffe holes. The trick is to not put kinks in the wire and thereby create false beats.
B. On the non-agraffe strings which had noise, I loosened the string over a step and then used a brass tool to tap the strings left, then right, then back to position. (Since I had to really work to get the relatively new hammers spaced and travelled, I didn't want to shift the strings permanently to new metal and have to backtrack.)

The budget didn't allow more efforts, and I was already beyond the work time I had really charged for.

What other tricks do you try?

When bending the wire you had better reset the string level or the dampers won't work. If the level was off before, it will be difficult to put it to the same as before. I won't do it. Also the hammer mating will suffer.

I have see other techs shove felt between strings on the non-speaking side. I assume this stabilzes the string-agraffe contact somewhat. That may help.

The biggest problem I find is hammer string mating. If the strings do not contact the hammer at exactly the same time, you will have phasing; a kind of a "wow" or "meow" sound. It is impossible to get clean unisons without impeccable hammer mating.

Make a hook from piano wire. Hook the shank from above and press hammer against strings gently. Pluck each string. All should block. If one rings, even a little, or produces a muffled pitch that is lower than the others, gently needle (sugar coat) the spot where the string hits. Even one small pluck may do the trick. Then check again.

Some techs take the action out and lay a thin strip of felt over the jacks with the hammers up. Then put hammers back down and replace action. Now all hammers will block when played IF the let off has been regulated properly. Then you can block each hammer easily and pluck each string.

P.S. Re:loud notes. Don't forget to try steam voicing and/or hammer softener. It's all guess work anyway if the hammers are too old and hard. Don't expect miracles.

Did the customer complain about the tone before you did the work? If they don't, I usually don't bother with the extra work. If they are not bothered, they may not even notice the improvement, and then you may have them wondering "Did I really need all that work?"

Thanks Mark,

You are certainly right about the importance of simultaneous contact across a hammer face with its target strings. Tone, checking, and flange wear are all potentially affected by this.

The hammers are fairly new - guessing 5-6 years with moderate use. This was their first filing and maybe the first real voicing from the evidence. Before I got to the voicing per se, I had already mated the hammers' strike point to the strings. On some of the unisons I could use "string leveling" to do the final mating. Since the strings are the originals, many wires could not be cajoled in that way. In those instances I did some fine filing to correct the hammer shapes on the bench by raising the hammers to a gauge bar and carefully correcting the angle. Once that was done, I ironed the hammers just enough to be sure no fuzz was loose on the surface of any hammer. The reason for the ironing is so that the hammers will have a strike point which is more like the contact surface actually will be after it is played for several hours. The iron is not very hot - just enough to mat down the surface fibers. This is time consuming, but this fine shaping, followed by the ironing, yields a mating contact that will stay that way, rather than change after a few sessions of playing. (The problem hammers then had to pass the plucking test again.)

After all that the actual voicing of the hammers began. In my mind I do not think of the above components as voicing, even though good voicing is impossible without all those preliminaries.

Time consuming but that is how some stability may occur.

Poking the out of level head does not repair the problem.

But I do that in front of the piano , I dont se how a jauge can repoduce the string plane of unison. Just raising the head you can look at its shape and know where to file, and you can often compare the crown plane with the edge of the hammer rail, that is enough for visual checking. (the edge of the hammer file or the edge of the sanding paper too)

A gauge on a bench allow to see the needs for papering/shank heating better, but for the strings plane a bubble jauge help a lot.

Voicing on new hammers is paid 12-14 hrs by the administration .
Once the hammer crown us shaped to the strings (to match the slant or level of the unisonn, as it may vary with seasons and plate shape)

Impacting strong the hammer on the unison while muting it with the finger pushing on the side with a rubber mute, really stabilize the strings level and the hammer. It can be ironed later I see that more for visual but I dont know for sure.

Really old strings are almost impossible to level.

Exceptionally loud notes, if, after all else has been done. can be made quieter immediately by a single needle between the string marks just behind the strike point, ( that is, the part of the hammer on the long string side of the strike point. Quite deep. This will add depth of tone, also. Not all the way to the core, as this can, contrary to popular belief, make the tone even louder over time. Check continually with the shift pedal to be sure you are getting the one needle in the best possible follicle. (it really is that location specific).

If it Is still loud on a soft blow, shallow needle on the edge of the string mark nearest the shortest side of the speaking length. Nearest the keyboard on a grand. Isolate the loudest string and do that one only for starters.

Always deal with the louder notes on a strong blow first. Make sure that is even before dealing with irregularities in the soft blow.

This is a legitimate technique. Busy techs have no time for temporary measures that take extra tools and time. I have never heard good tone from steamed hammers, at least when I have heard them a few weeks later.

Who is goIng to wait for an iron to warm up on a plug often across the room and wait for it to cool down before packing it away? It is a workshop tool. Hammers can be burnished with a flat piece of clean cold steel,( I have a few tool handles that answer that description) or even plastic to almost the same result if such a need exists in the field. Tamping the felt back down with something flat like the back of the needling tool handle (some of the better ones have an inlay just for that. ) is the time honoured way.

Then again, I am still off my medication and it's turning out to b a great excuse to tell it like it is and flagrantly divulge open secrets.

It is good to have some international advice, Kamin.

The guage I mentioned is a simple straight bar on legs that I carry always. Using it to judge the strike point of the hammer is only a relative judgement: In other words, if the hammer acted in the piano as if the left string was not being muted by the raised hammer, then the gauge showed the same, obviously the right portion of the hammer strike point needs filing down. I file a little, then iron the fuzz, recheck, the place the action in the piano again. I do this in groups. The first time perhaps there are 8-10 hammers which need attention. The next round, perhaps there are only three that are still not perfect, etc.

As you mention, visually inspecting the hammer crown angle is possible in other ways. What I like about my home-made bar is that the hammer is swung up to the actual height of the strings, so that I can see the real contact. I set the bar to the measured distance from keybed to strings. This seems to help me, but, of course, there are those many transfers of the action to the bench (and this Baldwin L action was fairly heavy).

Still, however, the bar is perfect, whereas the "level" of the strings may be really level or may be compromised, so the real test must always come by repeating the pluck test with the hammer in question raised into contact with the strings.

As you hint at, I think I will do fewer action transfers next time and try more of this fine work with the action only partly pulled.

Thanks to France!

And Hail to England, as well RXD!

Your progressive needling technique is the pattern I followed to a great extent, especially the loud test first. I restrict myself to deep shoulder needling for that first test and try to resist the temptation to correct too much at that phase.

I will now explain the "iron."

I carry a separate tool box labelled, "Voicing." In it is a Dremel tool, power cord, variable speed controller, a small propane torch and a hand held, old-fashioned iron intended to be heated by an alcohol lamp. (Obviously, an American can't wait for alcohol and therefore he must go for a TORCH!) The little iron is actually made of some zinc alloy (?) perhaps and heats up very quickly - perhaps six to seven seconds in the torch flame. I hardly ever use the Dremel (small rotary grinder). I also carry in the box some custom curved sand paper files for working in tight corners in vertical pianos.

When actually ironing with it, I reheat for less than a second per each group of three hammers or so. Strangely enough the friction of the hammer very precisely tells me when the temperature is hot enough. The test is this: When I can feel an increase in drag when rubbing the hammer, it is hot enough - any hotter and there is a danger of scorching. If I suspect that the iron my be too hot, I make contact at the shoulder first. That way any slight yellowing on the shoulder will warn me to not touch the crown with that excessive heat. After so many years of this, I seldom misjudge the temp. Yellowing can also at times reveal the presence of doping compounds. Ironing any doped hammers hotly, especially lacquered hammers, is inviting disaster, namely, a permanently crunchy contact point.

I always enjoy a phrase when it reveals to me a new thought. Yours was, "Isolate the loudest string and do that one only for starters." I had never considered that point. In the words of Spock, "I shall consider it."


Thank you for the information, RXD, as well as the confession!

Hello, yes working precisely in regard of the strings imprints is necessary, hence the time spend to obtain the same distance from the edge of the crown to the first string is well spend.

I learned to use graphite stick rubbed under the strings to verify where the UC pedal make its imprints (but I use it in normal position first)

On new or filed hammers the imptints are hardly discernable.

Is not your iron in brass ? I had a colleague who used a lot of heat, but it is not so good for the felt in the end I believe. It harden then loose elasticity, I wonder if it cannot kill the felt after some time, but I agree this is a way to raise brillancy (in the basses the crown react well to heat)


RXD, why not poking deep on the front ? to me light needling in front of the strings imprint (from to to bottom) is for the ppp nuances (while it lower a little the volume also)
I understand that some felt may move and come compacting a little more the underside of the front when the needling is done on the back

Poking deep on the back is less strong maybe ?

I often do some pre voicing before filing, often the felt have compressed, but the top of the shoulders have been needled so much they have benefit of some power from under, it facilitates the filing, too.

I always have been said to begin more low than the place I want to needle, it is not rare to find a "knot" or a haed spot that is under the hardened zone intended to be treated

About needling straight vertically, in the shoulder it cause maximum damage to tension, but near the crown it is yet radial needling.it may be deep enough and with one needle only. I like the way the tone thickens then (but I tend to consider the back of the hammer for more responsive for the spectra than the front.

Old hammers can be made alive with "deep" needling on the front of the imprints, vertically. The hammer get springy front to back, it makes a hole in the high spectra but the gain in dynamics is enough to be considered.

I find that goodie, :



It allows me to regulate the heat of any iron up to 500W

Very useful, as said RXD , the toolbag is really heavy if we take all those tools (mine is, lately I came with a luggage plus my regular tool box, both on wheels. and all by transports , metro , bus, train)

The tip is to have an adequate alphabet and enough memory to remind what is necessary on a few notes, then pull the action out on the knees and make the adjustments.

I dont really try to have the strings level if they all show a tendency to slant, as it is often the case on some part of the piano (sometime because of the capo shape, ofnen in the low medium because of soundboard crown)

It would be indeed ideal, but cannot be obtained always, or is ther eonly temporarly. The little string's level jauge is ideal to know what I am doing with the string hook.

i have no precise explanation, but the seasonal changes in moisture can be noticed with hammer mating problems - also of course uneven wear is due to the non centered placement of the head under the strings (for the UC).

A good theory about the inertia of the slanted hammers would please me. sometime on small pianos you cannot avoid to have more pressure on one side of the hammer pin, and in time the hammers get more loose than wanted on that side.

Adequate papering and shank burning may help to have a policed hammer travel . I believe that the Bluether solution with all hammer moldings glued at 90° but the slicing following the string angles, is a neat solution for backchecks and for the hammer center pin. I like the tone it provide anyway

Greetings

Isaac, in answer to your question, why deep needle in the back and shallow on the front?.
There used to be a belief among the ancients in piano technology that the melody comes from the front of the hammer, the harmony from the back. This whole belief system has been superseded by theories of equal needling both sides.
I have seen diagrams in old foreign books of this technique and even more drastic methods used by factories up to a hundred years ago. The library of congress in Washington DC is a fine source of international information from all eras.

My early interest in these things was nurtured by the library in a major provincial city that never threw a book away and the technicians there who were 'behind the times' compared to larger piano manufacturing centres and was taught some archaic methods alongside more modern methods.

These ancients, although their methods have been superseded, we're not idiots and their knowledge I have always found valuable and the results I have heard are mostly good, often superlative.

Another, more recent theory that was popular in USA when I was there in the 1970's was that, when hammers are sliced apart, the outside edges of the hammer lose tension compared to the inside of the hammer. To equalise these tensions, the hammer should be single needled deeply all around it's circumference.

Back to the older technique.

I was sent to a 30 year old Blüthner 7' for a days service, I was getting nowhere with standard needling and so I resorted to the more drastic measures taught me by an older tech. and the 'golden tone' that Blüthners were known for began to emerge. I remembered this sound from when I was an outside tuner for the London office of Blüthners some 40 years before so it was quite an emotional thing for me to hear this after such a long time and to have created it out of necessity. The client was also overwhelmed to hear his piano sounding so special. Not all Blüthners had this sound, it was a transitional time then and a different sound was emerging as fashionable.

rxd

Time honoured ways can be forgotten in the quest for progress.

What does burnishing achieve and does it work better on older types of hammer?

Burnishing is the same as ironing but without the heat. You can use the hammer iron without heating it up. It can be used on any kind of hammer if more attack is desired or used in conjunction with certain needling to bring the tone up. Usually, an older hammer has enough attack. It behaves exactly like ironing with the same result. I know exactly what I have instantly and long term so that I can work quickly. You can burnish a hammer even with light string marks with no fear of damaging it any more than playing would.

I can deal with most maintenance this way. If I need heat, I can generate enough by rubbing harder and/or faster.

Going into the city in this weather, I can carry all I need for any newish piano in the pockets of a big overcoat.

Sure it is incredible what an experienced tech can do with minimal tools and material (my back said me I must go that way

About Ironning with heat, I like to iron the flat side around the crown, then a light pass on the shoulders without really touching the crown make aneat looking hammer and abrighter tone (I would use the hot iron on the crown in basses, mostly)

Did not thought of the heat generated by rubbing , but I noticed how hot the sanding strip get when I file fast with a very fine paper grain 1500 or 2000 , that is certainly the source of the brightening obtained with that very fine filing

(but I cannot empeach myself to think of the fine particles of abrasive that quit the paper and insert in the felt

I just thought to point out that while some of the archaic needling techniques can produce a stunningly beautiful sound, that sound is locked into the piano and, at least in my observation, an advanced pianist will find it more difficult to vary the tone color through their playing.

Sure that the rebound is slowed so there is a good raise of fundamental and lowest partials but it is not possible to obtain a saturated or very percusdive tone. I wonder if adequate local impregation/juicing can help to correct that point, but the whole dynamic of the hammer is as a 2 shot gun, while usual voicing is more linear

I have several pianos that have been well played in that have had that treatment. They lose the 'magic' somewhat as they brighten but the tone remains clear and the voicing seems to be for the life of the hammer. It doesn't get harsh and the hammers retain their shape well. They don't seem to wear as fast.

I am surrounded by heavily used mostly newer pianos, or at least, newer hammers so hardeners are something I rarely have to resort to.