Fine points of drilling bridges

[David ilvedson]

Wouldn't a marking device with three prongs be superior to an 
awl?  They would be in perfect alignment with each other.  
Please comment.  I don't replace bridges but am interested.

David Ilvedson, RPT

Date sent:      	Sun, 13 Jun 1999 18:50:25 -0500
From:           	Carl Root <rootfamily@erols.com>
To:             	pianotech@ptg.org
Subject:        	Re: Fine points of drilling bridges
Send reply to:  	pianotech@ptg.org

> > For those of you who make bridges, I'd like to hear what kind of drill
> > bits you're using to drill the bridge pin holes, and the technique you
> > use.
> >  
> > Here's what I've been doing.  I've been laying out the pattern on the
> > fresh cap, marking it fist with a pencil mark, and then with a very
> > sharp awl (not deep, just a mark I can see, perhaps 1/32" deep), 
> 
> I would make a deeper mark without using the pencil as an intermediate
> step.  The awl is OK but you don't want the mark to produce a hole with
> a larger diameter than the bridge pin, so I suggest a nail with a
> diamter only slight less than the bit.  You could then go at least
> 1/16".  If the dimples don't line up exactly, you can exaggerate the
> angle of the bit at the start, than correct the angle.  
> 
> Carl Root, RPT
> Rockville, MD
> 


David Ilvedson, RPT
Pacifica, CA
ilvey@jps.net