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How much does filing hammers change their weight?

  • 1.  How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 06-22-2020 15:46
    The notion that filing hammers has a big impact on their mass, thereby impacting strike weight and key weighting, is fairly common. I have been skeptical from my own experience, noticing that when I gather pretty much all the felt from a major hammer filing and weigh it, it is generally less than 5 grams (divided by 88 to get an average). I have also filed to reduce mass, while also doing things like remove staples, cut wood from the moldings, and increase the taper. Filing didn't get much bang for the buck.

    Last week I had a major hammer filing job on a Steinway B, original hammers, never filed in over 15 years of heavy use (from a piano prof's house, of course), so I thought I'd quantify this more precisely. The hammers had an average groove length in excess of 10 mm through the mid treble. I removed one hammer assembly each from bottom tenor, top tenor, and top treble, weighing them before and after filing. Result? I removed 0.3 gm from each, thereby reducing DW by about 1.5 gm. 

    I'm attaching photos to document this. For each hammer, I photographed it with a ruler to show the groove length, on the scale, with its neighboring hammer after it had been filed (for comparison), on the scale after filing. And there is a photo of a filed hammer between unfixed hammers to give a good context.

    I hope this may be helpful for purposes of adding real data to picture of a very common part of piano service.

    ------------------------------
    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    http://www.artoftuning.com
    "We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda
    ------------------------------


  • 2.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 06-22-2020 15:51
    As I suspected, the photos, which were in meticulous order, ended up mixed at random. The numbers of the file names have them in the right order, as you look at them in the list in the library. In the viewer, they are random. No way to edit their order. Sorry about that.
    Regards,
    Fred Sturm
    "Art is not a mirror held up to reality, but a hammer with which to shape it." Brecht






  • 3.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 06-22-2020 15:54
    Fred,

    Good on you for this bit of research!

    In the interest of clarifying other possible misconceptions surrounding hammers, I have heard techs say that years of playing wears the hammers down (yes, true for the shape of the felt), and renders them lighter. I have yet to wrap my mind around how they would lose weight withOUT filing.

    Your thoughts?

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 4.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 06-22-2020 15:59
    Hammers will lose some mass from the crowns, as the felt wears off. So to be more precise, what I showed was 0.3 gm per hammer removed by filing from the shoulders. 0.1-0.2 gm might be added to that for what had worn off the crowns. So those fairly worn hammers may now be as much as 0.5 gm lighter than when new. They might make it through another similar filing, and be voice-able, but that would be getting iffy.
    Regards,
    Fred Sturm
    "Travel is fatal to prejudice, bigotry, and narrow-mindedness." Twain






  • 5.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 06-24-2020 12:47
    It depends on how much filing.  In this case, with upper scale hammers that you've shown, it's not much.  But it can be, especially with hammers lower in the scale where the strike point has gotten even wider and significant material needs to be taken from the shoulder of the hammer to recapture the original overall shape.  And with multiple filings over time the amount can become quite significant.  Hammer weight differences between note 26 and note 88 (let's eliminate molding differences between bass and tenor/treble hammers) can be as much as 1 gram per octave.   That difference is entirely the amount of felt on the hammer.  It's not difficult with even one good filing on a flattened hammer to reduce the hammer size by one octave, effectively.  That's 5-6 grams of static weight and perhaps more significant in terms of inertia.  While we don't necessarily have to worry about recalibrating touchweight with one relatively light filing, over time it's worth considering if that becomes an issue with the player.

    ------------------------------
    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
    ------------------------------



  • 6.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 06-25-2020 03:22
    How would you rate the density of the felt in these hammers? Physical size notwithstanding. 

    In my experience -- but not having weighed the results as you have -- there will be more variation in hammers that started out life as hard-pressed, dense, and relatively massive hammers than you have found in these hammers. 

    Again, without having weighed and recorded the results, I have treated dense 'Asian' hammers with a mixture of alcohol and water, had them swell and, when dry, sanded them back to original size. Listening to the result and repeating the process several times until the hammers would no longer swell appreciably. At this point I found that I could remove one or more leads from the keys and still have a static downweight in the 50 - 54 gram range. 

    This goes back four or five decades and our methodology was rather crude so I'm sorry I can't be more precise, but I suspect the results achieved -- the reduction in mass -- will depend somewhat on how the hammers were originally pressed. 

    ddf






  • 7.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 06-25-2020 15:32
    The Steinway hammers in the photos are relatively "soft" pressed, certainly softer than Hamburg. I'll comment that filing is limited to the area above the staples, hence will not remove lower shoulder felt. Thus, visual comparisons with hammers an octave higher might or might not correspond to the same mass.

    I simply offered the results as a way to document actual fact rather than assumption or extrapolation. I figure that in the absence of Ron Nossaman, somebody needs to do that once in a while :-)

    Regards,
    Fred Sturm
    "We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda






  • 8.  RE: How much does filing hammers change their weight?

    Posted 07-01-2020 13:51
    I, too, have often wondered about how much of an impact hammer shaping has on hammer weight and touch weight.
    In a much more primitive experiment that yours, Fred, I grabbed a few hammers to see what one gram of felt removal actually looked like.  Instead of filing (and trying to collect all the fuzzy and floating bits, I took the sharpest knife I could find and carved off a layer of felt, trying to maintain a semblance of hammer shape as much as possible. It made it easy to weigh the removed material.  By the time I had removed enough felt to constitute one gram, there was not enough left of the hammer for any kind of reasonable music making.

    ------------------------------
    Jurgen Goering
    ------------------------------



  • 9.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-01-2020 19:46
    Interestingly, cutting felt off hammers, with a "felt knife," was common practice in the later 19th and early 20th centuries, according to instruction manuals. They didn't have multiple grades of sandpaper and modern abrasives. They were likely to have glass paper at best (ground up glass glued to yardstick, to the best of my knowledge).

    I do it occasionally, especially when I have an individual hammer that has deep grooves and needs to be realigned to its strings. 

    But to Jurgen's point, yes, 1 gm is a heck of a lot of felt. Unless you remove it by seriously increasing taper (removing wood as well), it will leave very little to work with.






  • 10.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-01-2020 19:49
    Autocorrect turned cardstock to yardstick. Didn't notice until it posted. (Glass paper).
    Regards,
    Fred Sturm
    University of New Mexico






  • 11.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-01-2020 21:15

    Hi-

    I would agree that generally the assertion here is correct, that in most cases our typical hammer shaping/filing does not remove a lot of weight.  At least when the hammers originally had a good shape to begin with, that is true.  In some cases hammers that did not get any proper shaping originally, can have a great deal of excess weight.  If you regularly weight-off your hammers for a smooth strike weight every time, it is indeed possible to remove 1 gram when necessary.  In that case, you will likely be removing staples, and cutting away some of the lower shoulder bulk.  Even in the treble I've received new hammers out of the box that were as much a 1 full gram too heavy.  That is not the way I like it, but it happens. My preference is to remove about .3 to .5 grams for a proper shape on new hammers and get the weight just right.  If doing that makes the hammer a bit too light, then we add lead. 

    I'm not sure exactly how this correlates to the discussion about typical hammer shaping, as our goal then is usually to remove as little felt as possible to restore acceptable shape.  I would only assert that it is indeed possible to remove more weight if needed, and some hammers need it.  

    I recall one case of a new Steinway D we purchased for the hall in 2003. In about 2015 the time came around to install new hammers. The new factory hammers I received were each on average 1.0 to 1.3 grams heavier than the originals all through the mid-range.  I have that data recorded but that's what I remember without looking up the records. The players could definitely tell a difference and were most pleased when I re-balanced closer to the original hammer weight.  

    thanks,
    Dennis Johnson
    St. Olaf College






  • 12.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-01-2020 22:25
    Some actions have the DW set at the lowest practical limit for the leverage and inertia properties.The pianist may find the feel excellent when new. But after the hammers get work hardened to the point the tone is not proper anymore and the hammers get shaped, the pianists often perceives the touch too loose or flyaway. Even though when you measure the DW it has only reduced 2 or less grams, the inertial balance has gone off the deep end, into too easy to play.

    Removing a front lead to raise the DW by as much as 7 or 8 grams will usually meet pianist satisfaction. Even though it now weighs heavier than original specs.

    What you will notice if you research these things is that as inertia drops, DW can rise significantly from "factory" specs and the action will still be perceived as "light".

    ------------------------------
    Edward McMorrow
    Edmonds WA
    425-299-3431
    ------------------------------



  • 13.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-02-2020 03:07
    The simplest way to do this is just take a hammer out of a set and weigh it and then find a hammer higher in the scale that weighs a gram less and compare the sizes of the hammers.  The difference (assuming the hammers are the same width) is all felt.

    ------------------------------
    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
    ------------------------------



  • 14.  RE: How much does filing hammers change their weight?

    Posted 07-02-2020 16:11
      |   view attached
    I am not sure this is a very precise method\. I have seen new hammers that varied by 1 gram form one hammer to its neighbor.  Also, the core, which is significant in the hammer weight, changes dimension if you go up or down by a few notes.

    Here is a jig I built for weight reduction by tapering hammers on shanks. It was a bit of a job to build but it works well. I put 2 hammers in it at a time. Left side of one, right side of the other gets trimmed on the table saw. The holes in the jig are calculated for maximum aerodynamic efficiency ;^)


    ------------------------------
    Jurgen Goering
    ------------------------------



  • 15.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-02-2020 16:26
    In practical terms, you will not be able to file a hammer to match the profile of the lighter hammer higher in the scale, due to the presence of the staple (unless you remove it). Our normal filing techniques approximate but do not mirror precisely the original profile, since we must confine ourselves to the area above the staple. Thus, any theoretical comparison with higher hammers will have to be fudged: you’ll need to take more off the crown (where you don’t want to take it), or perhaps use something in the way of a chisel/felt knife and remove felt below the staple (easier if you remove the staple).

    My original post was referencing normal filing as opposed to consciously choosing to remove mass. Jurgen is correct that there may well be additional variance in mass, which usually happens in cutting apart the hammers. Some sets are uneven by as much as 1 mm variance in width, which equates to quite a bit of mass (10% or so).
    Fred Sturm
    fssturm@comcast.net
    www.artoftuning.com
    http://fredsturm.net
    "Tradition is not the worship of ashes, but the preservation of fire." -Gustav Mahler




  • 16.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-03-2020 12:19
    Depending on the section of the piano most of the weight is in the felt, not the molding.  It's quite easy to take more than a gram of felt off in certain parts of the piano, especially with multiple filings over time.  Fred posted a treble hammer that got fairly light filing.  Of course the change in the top of the piano where the hammers have less felt will be less.  But here's an example of just how much things can change.  

    The outer layer of felt on this hammer, easily removed by filing, is 1.4 grams.  On a AR of 6 that' 8.4 grams and the impact on inertia is perhaps more significant.  I would not underestimate the impact on touchweight and touchweight dynamics by filings, especially multiple filings over time.

    ------------------------------
    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
    ------------------------------



  • 17.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-03-2020 14:57
    David,
    Actually I posted three hammers, from bottom tenor, top tenor, and mid treble. I was surprised and interested to find that each of the three was reduced in mass by 0.3 gr. I wouldn't call it a light filing when the grooves are at least 10 mm long. 

    Regards,
    Fred Sturm
    "Since everything is in our heads, we had better not lose them." Coco Chanel






  • 18.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-03-2020 15:54

    The pictures I posted speak for themselves. Filing can contribute to a significant reduction in weight without them being rendered useless for music making, as Juergen posted. As your experiment suggested it may depend on how you file them and, of course, it depends on where in the scale. If you try and recapture the original shape, removing material from the shoulders, that will be more significant than, say, just flattening the high shoulder. But I stand by my statement that I would not underestimate the potential effect of hammer filing especially over time and multiple filings. Even if reduction in touchweight of 2-3 grams (.4-.6 grams of felt) is not insignificant considering techs do differentiate as significant  setting the BW between 35 and 38 grams, not to mention the impact on inertia. And there are other factors. Even a relatively light filing as you have done can impact the repetition spring, for example. 

    Most of these significant reductions will happen over time and multiple filings. But I encounter that all the time on old pianos with original hammers where the BW is around 30 grams, certainly nothing near the original setting. 



    ------------------------------
    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
    ------------------------------



  • 19.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-03-2020 16:43
    David,
    I make no claims other than to have presented objective data, from actual field filing. In my work, this was a fairly extreme filing. (I am still rather puzzled by your repeated characterization as of it as a "relatively light filing.") If you care to examine what I did, I made it easy for you: I photographed each hammer I filed right next to its neighboring hammer in each case, before I took the after weight. And I took an additional photograph of the highest hammer I filed in place, attached to the rail, for a further perspective. 

    I'm sorry that the order of the photos I attached to my post was screwed up in the uploading process, and apparently that cannot be changed by the user in the editing menu. In order to get around that, I have done a second upload of those same photos directly to the library,  which process allowed me to place them in the correct order.  Please take a look (it's quick and easy). I think you will discover that I matched the shoulder profiles pretty well, allowing for the presence of the staples, which limit the possible arcs.

    Your photos, David, do, indeed, speak for themselves, and are also objective. They are, however, a fabricated scenario, not one from actual practice. They mimic what we may think we do. And it is quite likely that your hammer felt is denser than mine  - looks like Renner rather than the Steinway hammers I filed.

    Does filing have an impact on touch, response, inertia, etc.? Yes, of course. How much effect does it have in the ordinary course of our work? That is what I have aimed at showing. I provided one example, and an easy one for anybody with a scale to replicate. 

    Rather than presume, based on conjecture, I suggest we measure, and specifically measure the results of what we actually do. Pretty simple concept.  
    Regards,
    Fred Sturm
    fssturm@comcast.net
    http://fredsturm.net
    www.artoftuning.com
    "Art lives from constraints and dies from freedom." Leonardo









  • 20.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-03-2020 17:19

    I'm responding to two claims, one, that filing is not significant and two, that you can't take off enough felt to make a difference without rendering the hammer unmusical. Both, I believe, are false and easily measurable.   Removing .3 grams of felt is, in my opinion, a relatively light filing. 


    Actually, the accurate way to do this is to measure the strike weight before and after. I'll do that later and post the results. But from experience I can tell you not only is it significant but it can be very significant! In the 90s you may recall, Steinway produced hammers of the genus puffballus giganticus. I still run into those pianos. It was routine with many techs to do a very heavy filing not only to improve the tone (challenging the unmusical claim) but also to lower the touchweight which tended to be very sluggish at that time. It was not uncommon to drop the BW 4-5 grams in midrange of the piano, more in the bass and, of course less in the treble.  The reduced mass in the treble also helped with clarity and sustain by reducing contact time. 


    While I agree that a light filing does not make a large difference, it does make a difference and if the hammers are filed multiple times, well now we're talking real money. 


    Even so, ~2 grams (.3 x AR of 6, eg) is not insignificant. If we're asked to balance an action at 50 grams DW do we tell a customer, well I set it plus or minus 2 grams but that's not significant?  I don't think so. 


    I'll do some SW tests later, when I have time, and post the results. 



    ------------------------------
    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
    ------------------------------



  • 21.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-03-2020 17:35
    Let me also add that a hammer which is severely flattened on the crown has already lost some mass so our filing only adds to that. If our goal is to maintain the same BW as when the hammer was new (and it isn't always) then we should pay attention to that.

    ------------------------------
    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
    ------------------------------



  • 22.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-06-2020 13:03
    This is a midrange hammer.  









    ------------------------------
    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
    ------------------------------



  • 23.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-06-2020 13:30
    David,

    Comparing photos 1 &2, how are we to account for the 0.1 gram difference? Measurement tolerances? Or did that bit of felt actually "go" somewhere (in which case, where)?

    Thanks,

    Alan

    --
    Alan Eder
    Registered Piano Technician, 
    Piano Technicians Guild






  • 24.  RE: How much does filing hammers change their weight?

    Posted 07-06-2020 14:31
    I think the difference is between photos 2 & 3.  To remove .1g you would use a small radius drum sander and remove it from under the staple on the backside, feathering the taper. Or sand the molding slightly.  This is where an oscillating spindle sander comes in handy.

    ------------------------------
    Regards,

    Jon Page
    mailto:jonpage@comcast.net
    http://www.pianocapecod.com
    ------------------------------



  • 25.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-07-2020 02:29

    The pictures are all of the same hammer

    Picture #1 is the hammer in its original condition. 

    Picture #2 is after I filed the strike point flat, typical of what we might fine in a worn hammer  That reduced the SW by .1 grams  

    Picture #3 is after I filed the hammer to recapture the original shape which resulted in a further reduction of .6 grams  

    So, by virtue of wear plus filing to recapture the shape, the hammer was reduced by .7 grams.  

    I'd call that significant in terms of touchweight, both static and dynamic.

    ​​

    ------------------------------
    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
    ------------------------------



  • 26.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-07-2020 11:42
    Same sort of experiment, different results. Note that the reduction in mass is the same whether measured as strike weight or as the whole hammer assembly. It took a lot of filing, more strokes than in the example I used to open this thread. I expected the mass of shoulder material removed would have been more. Not too surprised by the mass of crown removal, as that is the densest felt.
    Regards,
    Fred Sturm
    University of New Mexico






  • 27.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-07-2020 12:45
    Not really that different a result given the sample size.  Yours was reduced by .5 mine by .7.  You left much more of the shoulder intact than I did, especially on the distal side of the hammer.  

    The message, as I see it, is that light filing doesn't change the SW that much.  Heavier filings, especially multiple filings over time, can indeed change the SW and the hammers lower in the scale have a greater potential for change.  This, while the hammer still remains capable of reasonable music making.  

    So if you are one of those techs who obsesses about smoothing your strikeweights and balance weights to the .1 grams and matching SW to AR then it would be best to pay attention to the effects of filing.  Changes in the SW can result in significant enough changes to both reduce BW and inertia.  A four gram drop in BW can be enough to necessitate the removal of one  whole 12 - 14g lead, if you happen to use accelerated action leading patterns, about 1/3 of the distance between the balance pin and the front of the key That is if you want to preserve your original BW.  Of course the inertia won't be compensated for by doing that.  You would have to add weight back to the SW. 

    Most of us don't or won't do that in practice.  But these days, with so many people using component balancing systems and precise weigh offs such as Stanwood methodology, it is not insignificant.

    ------------------------------
    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
    ------------------------------



  • 28.  RE: How much does filing hammers change their weight?

    Posted 07-07-2020 13:17
    If the SW reduction adversely affects BW, you can add shank clips to compensate. Quick, easy, reversible.

    ------------------------------
    Regards,

    Jon Page
    mailto:jonpage@comcast.net
    http://www.pianocapecod.com
    ------------------------------



  • 29.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-08-2020 02:45

    Jon

    And something like that would probably be the best solution as it maintains both BW and inertia, at least if that's the goal. Also the clip can be easily moved to accommodate subsequent filings.


    In fact, I've sometimes considered attaching clips to the center of the shank at the outset. Not only would that allow you to compensate for what we are discussing, but you could also change the weight and dynamics of the action (not to mention the tone) by just sliding the clip up or down the shank and altering the SW. 


    Fred

    The question was never what gives "the most bang for the buck" and where we should spend our time. The question was whether filing significantly changes the SW. You claimed a marginal difference. I'm suggesting, and demonstrating, that there can be a significant difference. If you care about maintainIng the original touchweight dynamics then you would be advised to pay attention. If not, then don't.  There may, in fact, be times when a reduction in hammer mass is desirable for a variety of reasons  And that too is demonstrably achievable to some degree. 

    Many on this list do rebuild actions and take care to produce a targeted and uniform touchweight, both static and dynamic. For many that's SOP.  My input is only to question your conclusion about significant change for the sake of those for whom it matters. 



    ------------------------------
    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
    ------------------------------



  • 30.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-07-2020 18:05
    The total difference in mass reduction isn't all that much. What raised my eyebrows was the 0.1 gm for the crown, compared to the 0.6 gm for the shoulders. That's what made me want to do my own measurements - largely to know a little more about what might come off the crown during wear. And it turned out my crown measurement was 0.3 gm, shoulders 0.2 gm, quite a bit different picture from 0.1 and 0.6. 

    I suspect part of that came from measurement variance. Strikeweight is troublesome to measure to the same 10th of a gm consistently, and in any case the scale is giving you + or - 0.05 gm (If the high end is 10.045 gm. and the low end is 9.855 gm, the scale will tell you 10.0 and 9.9, for a difference of 0.1, where the difference is actually almost 0.2. Just placing the whole assembly on the scale gives you the same difference value, and takes the additional SW variability out of the picture.

    You complain I didn't take enough off the shoulders. Here is the hammer I filed next to its upper neighbor. The photo speaks for itself.
    one after filing, the other being the neighboring hammer

    As for the utility of obsessing about  "smoothing your strikeweights and balance weights to the .1 grams and matching SW to AR," I'll leave that to those of you who do that. I find that focusing on other aspects of action prep give me far more bang for the buck, and I don't have many wealthy clients here in Albuquerque (they live up the road in Santa Fe). 

    ------------------------------
    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    http://www.artoftuning.com
    "We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda
    ------------------------------



  • 31.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-03-2020 12:15
    Thanks for sharing this Fred! I have to admit the results surprised me.

    ------------------------------
    Nathan Monteleone
    Fort Worth TX
    817-675-9494
    nbmont@gmail.com
    ------------------------------



  • 32.  RE: How much does filing hammers change their weight?

    Registered Piano Technician
    Posted 07-04-2020 10:16
    I filed the hammers I posted about for UNM piano professor Falko Steinbach, who was needing to record for a virtual concert. Here is that virtual concert.

    ------------------------------
    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    http://www.artoftuning.com
    "We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda
    ------------------------------