[pianotech] Broken Drill Bit in Bridge

[Terry Farrell]

Thanks to all for the suggestions. I'll have to look at my tenon cutters - I know I have a 3/8" and maybe a 1/4" - and then order either the 3/8" or 1/4" screw extractor - preferring the smaller to minimize cutting of the bridge. I wish I were as resourceful as Ron N - and/or had the skills and motivation, but I think I'll opt for the slightly $$ier but easier route of just buying the stuff. Thanks again.

Terry Farrell

PS: I mean my "friend" will buy an extractor - and, and I'll likely lend him my tenon cutters......  ;-)

On Aug 11, 2012, at 8:55 PM, Nicholas Gravagne wrote:

> Terry,
> 
> Your friend may be interested in this little tidbit :)
> 
> I posted this little idea on this list a while back. 
> 
> First, make small pattern of the bridge holes for later use. Next use a hollow screw extractor like Issac suggests. Remember, the pin is at an angle. There is no way to really do a nice neat job at this phase of the repair. Once the root canal is done, fill the hole with a dowel, glue in and trim flush with the top of the bridge. The purpose of the dowel is solely to provide some material for a 1/2" forstner bit brad point to center on. 
> 
> Next, use your 1/2" plug cutter to make a maple plug (1/2" should work). Note the direction of the maple material as to planing with and not against the grain, and mark your plug accordingly. With the forstner, drill down to a depth a bit less than the height of your plug. Glue in your plug; it should stick up a bit and will extend partly into the notch area. Trim down with a sharp chisel, sand smooth and DAG the area. 
> 
> Next re-drill your bridge hole (or two holes) and chisel-cut the notch in your usual way. See photos. 
> 
> Nick
> 
> On Sat, Aug 11, 2012 at 4:09 PM, Terry Farrell <mfarrel2 at tampabay.rr.com> wrote:
> Ummmm, a "friend" asked me to pose the question: How best to extract a broken drill bit from a bridge pin hole? The top (broken end) of the bit is about 1/8" below the top of the bridge. Any suggestions short of gouging out a hunk of bridge?
> 
> If I get a good suggestion, I'll pass it on to my "friend".  ;-(
> 
> Thanks!
> 
> Terry Farrell
> 
> 
> 
> -- 
> Nick Gravagne, RPT
> AST Mechanical Engineering
> <Bad BR hole.jpg><Forstner.jpg><Plugged BR Holes.jpg><Maple Plugs.jpg><Plug Trimming.jpg>

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