clean - don't ream!

[Al Jeschke]

>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
>    
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I can't say that I ever had a problem getting accuracy with drill bit
reamers.  The selected drill bits to become reamers were the nearest
diameter larger than what was needed for making the desired diameter
reamers. My reamers are not tapered, but the corners of the leading edges
are rounded off so that they will not grab or marr the sidewalls of the
tuning pin holes.  

Depending on the hardness of the block, or moisture in the block, allow
.007" to .012" under tuning pin replacement size, which can easily be done
with custom made reamers.  Good advise given is to test in an old block.
That will give some idea what to expect, but then also do a test hole in the
block to be repinned.  There may be a difference in hardness.  Alberta is
dry country, but in summer I prefer to dry the pin blocks before repinning
or restringing.
 
As for drills - we all have our preferences.  I prefer a little more power
and to run the drill slower, especially at the entry of each pin hole.  This
will give added control, making alignment easier.  Experience (with care) is
the best teacher, and after `you done it' you'll be surprised how easy it is.