[pianotech] Size of Pinblock Drill bit?

[Ed Foote]

Hmm, Ok, I have been using homemade chasers instead of reamers, who knew?  
   
   The  K bit that I use to chase a Steinway 2/0 block prior to repinning with 3/0 pins manages to cut something out of those holes with the cutting edges I left in the middle of the bit.  Especially down at the bottom, where there is often uncompacted pin block holes drilled for the 2/0 pins. 
     I don't know what is being sheared off the inside of the holes, but there is wood removed when I do this, even though the bit is supposedly smaller than the hole should be.  
Regards, 


Ed Foote RPT
http://www.piano-tuners.org/edfoote/well_tempered_piano.html



-----Original Message-----
From: Jim Ialeggio 
<I have made my own pinblock reamers from bits in which I grind away all 
the cutting edges for the first inch or so of the bit. It makes for an 
accurate pilot without chewing a
sideways hole on the way in.

This is interesting and makes a lot of sense.

So, what exactly is the cutting action of a reamer?  Is is simply a 
scraping action?  If so, what keeps the 1st hole's wall fibres from just 
bending over rather than actually being sheared off ?

 
 
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