clean - don't ream!

[A440A]

Rob writes:

>Regarding reamers,  I'm hearing that it's hard to get accuracy.  Also, none
>of the respondents gave their recommendations for actual reamer size versus
>actual pin size.  I would think this is the most important factor in getting
>good torque.
> Also,  what about using a drill
>bit of proper size instead of reaming or cleaning, and (assuming I mike each
>pin and try to get good consistency, how many thousandths undersize would
>you drill?
 
    I agree,  it is time for the numbers.  What is desired is a consistant
result, first, then the decision can be made how tight. 
     I use a drill bit, and grind the first inch or so into a non-cutting
smooth taper(slight, maybe losing .010 of diameter at the tip.  This allows
the bit to get aligned in the hole before removing wood.  There is no chance
of the first time user doing 250 holes perfectly, so you absolutely have to
practise the technique on an old block.  This is a delicate skill, and how
many delicate skills are done well the first time? 
    With the proper size bit,(i.e., easily replaced reamer....)  picked and
ground,  I use a 1/4" drill for it's lightness.  The sensitivity part is
simultaneously guiding it down straight and not letting it go down so fast
that it digs in.   The former requires softness of touch, the latter requires
strength.   Get used to the speeds that grab, or what it feels like to run in
and out effortlessly.  The cleanest results seem to come from full speed,
medium feed.  It requires practise and can be learned in about a half hour.  I
control the heat with a nearby tube filled with alcohol and water.
      I don't ream to 3/0 pins, there is so little margin of error there, with
tolerances from three elements stacking up that I go to 4/0 if the block is
the least bit inconsistant.  
       For sizes:  I have nice results from using a .280" ream for 4/0 pins.
The 2 1/2" lengths are preferred.  On an older model Steinway,  this will
usually begin  my torque readings at 120 in/lbs, which drops to approx 110-100
in the first year, and stays there. 
Hope this helps, 
Ed Foote