Bolduc Block - Bit Size - Torque

[Farrell]

Perfect. Thank you Ed. I seriously considered using the 1/0 pins, based on what you have written before and the fact that I love tuning with the smaller pins. But basically, I just didn't have the, a, ba--z to do it - this is on a M&H with no bushings (I realize you use the 1/0 on similar pianos). Maybe next time. And yes, I don't like the 180 in.-lb. torque - I'm trying to make my way to a more moderate level. 

But using your numbers, you are installing a 0.276-inch pin into a 0.042-inch hole. The size difference is 0.034 inches. If I were follow this, but only using a 2/0 (0.282") pin (which I am), I would be drilling a 0.248-inch diameter hole (which is what is recommended for the Bolduc block. But I am getting 180 in.-lbs. with a 0.263-inch diameter bit. This is what concerns me. Maybe it is silly, but I worry that for some reason the torque is initially artificially high and maybe its going to drop a bunch after a while (I actually realize that is unlikely, but why so high torque with such a big bit?).

Is it unusual for a proper bit size to vary as much as 3/100ths on a Bolduc block to produce a specific torque? Is it possible that the two-step drilling method creates conditions such that a much larger bit is required for the final pass to produce the same size hole as a 0.248-inch bit would do with one pass?

Terry Farrell
  
----- Original Message ----- 
From: <A440A@aol.com>
To: <pianotech@ptg.org>
Sent: Tuesday, June 17, 2003 3:49 PM
Subject: Re: Bolduc Block - Bit Size - Torque


> 
> > a new Bolduc quarter-sawn  (more-or-less) hard-maple pinblock. I am using 
> Ron Nossaman's two-bit
> > drilling method. I started out with a final drill size of 0.25-inch 
> > (actually the drill bit that Pianotek sells specifically for the Bolduc
> > blocks - it is actually about 0.247-inch). I was consistently getting
> >an  initial torque exceeding 200 in.-lbs. . I am getting an initial torque 
> (right after pounding the
> > pin to stringing height) of about 180 in.-lbs.
> 
> Yikes,  this is WAY too tight for finesse.  I use the Bolduc blocks with 1/0 
> pins and a C drill. I drill them in one pass.  Average beginning torque is 130 
> in/lbs,  after one year I see near 115 in/lbs.  The oldest block that I have 
> done this way is 5 years old and it is still at 110 in/lbs and tunes like a 
> dream.  That particular piano got tuned 85 times last year,(recording studio, 
> where every tuning has to hit A-440).   
>   I use a D bit in the top octave, it reduces the torque by about 10% and 
> makes the top end a lot easier to tune.  
>    I use the 1/0 pins because if there were to ever be a problem, I can solve 
> it with a "normal" pin.  
> Regards,
>  Ed Foote RPT 
> www.uk-piano.org/edfoote/
> www.uk-piano.org/edfoote/well_tempered_piano.html
>  <A HREF="http://artists.mp3s.com/artists/399/six_degrees_of_tonality.html">
> MP3.com: Six Degrees of Tonality</A>
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