[pianotech] Size of Pinblock Drill bit?

[Douglas Gregg]

Mike,
I have been off this site and gone over to Google so this might be a
little late. Instead of a nubbed bit as you describe (and I am still
not sure what it is) I suggest chucking your bit in a hand drill and
with the drill running, run it at a slight angle from parallel against
the side of a grinding wheel that is running. The result is tapering
the tip and perhaps an inch of the drill  bit to a smaller size. That
can be used two ways. It allows the bit to enter a smaller hole
without chatter and guides the bit in just like the taper on a tap for
threading.  In the more extreme, the bit can be ground to nearly a
point that replicates the profile of a wood screw and makes a perfect
pilot hole for a wood screw without using one of those wobbly flat
bits to drill wood screw holes at a taper. Try it, you will love it.

Douglas Gregg
Classic Piano Doc
Southold, NY

Message: 1
Date: Thu, 07 Mar 2013 08:22:21 -0600
From: Mike Spalding <mike.spalding1 at frontier.com>
To: pianotech at ptg.org
Subject: Re: [pianotech] Size of Pinblock Drill bit?
Message-ID: <5138A29D.8030708 at frontier.com>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"

Thanks, Jim.  Totally clear now!

Mike Spalding

On 3/7/2013 7:31 AM, Jim Ialeggio wrote:
> ------------------------------------------------------------------------
> Mike Spaulding wrote:
>
> <Nubbed? By hand? more detail please!
>
> Ouch!!  I read back over my post and realized I misstated what I meant
> to say.
>
> Here it is corrected with a pic of the SLOW SPIRAL, nubbed bit:
>
> 1st pass 1/4" fast spiral, or whatever you bit you want to use...not
> too picky
> 2nd pass - SLOW SPIRAL nubbed run through with a hand drill. Sized as
> per final target torque and block type, by test.
>
> The nubbed bit simply has the cutting edge  ground off (eyeballed on
> the grinder) to about a 90 deg angle at the OD of the bit's leading
> edge. See pic.
>
> Just to confirm, I wrote fast spiral nubbed in my original post...I
> meant to say that the 2nd pass is SLOW SPIRAL nubbed!!!
>
> I'm actually thinking of having WL Fuller regrind these so that the
> 1st 1" is a 1/4" non-cutting pilot step drill... but haven't had that
> done that yet.
>
> Jim Ialeggio
> --
> Jim Ialeggio
> jim at grandpianosolutions.com
> 978 425-9026
> Shirley Center, MA
>