Dremmels on hammers was RE: mini belt sander for filing hammers

[David Nereson]

David Ilvedson wrote:

>David,
>
>What is your criteria for filing?   When you file frequently do also fit hammers/strings...maybe only on the concert instruments?   Do you find you need to even out the voicing after a light filing or is the voicing stable...?   Do you use the Dremmel for light filing or ?
>
>David Ilvedson, RPT
>Pacifica, California
>
>  
>
     
    What I'm looking for is a way to save my wrist and elbow joints, and 
all that repetitive motion involved in filing hammers -- a way to file 
hammers with a power tool without taking off too much felt or making 
divots.  It could be light filing or heavy -- I can always change the 
grit on the sanding drum or belt.
     I very rarely get to do any concert work.  Or even fine grands in 
the home.  Even the few wealthy who do own fine grands use them more to 
make their living room look classy than for music. 
        I could count on one hand the number of pianos on which, in 27 
years, I've filed hammers more than once. 
     Most filing I do is on pianos that haven't been serviced in 10 to 
80 years.  The string grooves are often a quarter inch deep in the 
bass.  No exaggeration.  Not quite as deep in the treble, but on the 
ones that need repinning badly, it looks like someone took a saw and cut 
a half-moon shape off the tip of the hammer.  Oh I know, if they're this 
bad, they should get new hammers, but most people don't want to spend 
$500 or even $250 on their old upright, Hamilton studio, or Wurlitzer 
console.
     The only time I'm doing a light filing is on a relatively new piano 
that has cupped hammers (like Kimball consoles) or has hammers that need 
filing mainly to make the tone firmer, rounder, more robust -- just to 
take off the outside layer of loose, "dead" felt and expose the 
tensioned stuff underneath. 
    But I will try the Dremel again with a lighter touch, worn-down 
sandpaper, and in the direction of rotation, rather than against.  I 
hadn't thought of that. 
    No, for hammer-to-string mating, I use a paddle or a "shoeshine" 
strip of sandpaper. 
    And when the hammers are not angled, both on verticals and grands, I 
use gang filing whenever I can.
    When hammers are terribly worn, usually filing them makes the tone 
more even from note to note than it was before, because now they're all 
the same shape, without the deep grooves.  But on closer listening, yes, 
they still need voicing.  As for voicing after a light filing, I don't 
know -- most of the ones I run into need a major haircut.  If they're 
very shallow grooves, sometimes I will steam them, or even let them be, 
and just voice. 

    I checked the Micro-Mark website and they have a mini belt sander, 
but it's like a shrunken belt sander for sanding boards -- too big and 
unwieldy for piano hammers.  Well, maybe on grands (?)  Not sure how 
wide the belt is. 
    But the Proxxon unit in the Model Expo catalog is on sale for a bill 
(normally $159.99).  Looks like it might be just the thing.  It's also a 
bit big, but with a vertical action in a cradle, at the right angle, it 
looks like it just might work.  I think I'll take the gamble, and if 
it's not right, I can use it for other things (a huge power fingernail 
file, or maybe a chipped key lip reducer).
    --David Nereson, RPT