Ed,

If you are drilling .008" and .010" diameter holes into .021" thick
panels (assuming that you are drilling this thing one high), a flute
length of .060" would be what I would recommend.  This flute length would
also allow for up to four repoints if you so desired. I would also
recommend that the web be slightly thicker and the tool be unrelieved if
you are having issues with wander.  As far as availability, most of the
drill bit manufactures will provide "special builds" to their customers.
If you cannot get a "special build" tool from your drill vendor, you
might want to try peck drilling.  Typically, a three peck cycle is the
norm for fixing positional and hole quality problems.  This would also
eliminate breakage if it was a problem in the past.

Questions to you:

1.   Are you using any entry material and if so, what kind?

2.   What is the layer count /construction?

3.   Is there any heavy glass in the build?

4.   Have you verified the  spindle runout is within spec?

5.   How many hits are you putting on the tools before you retire them?

Important information needed to help solve your problem.

Mark Ford

On Wed, 10 Sep 1997 14:38:10 -0500 Ed Cosper <[log in to unmask]> writes:
>I am currently developing a special process that requires very
>accurate =
>placement of small diameter holes. I have run into some problems with
>=
>drill wander / deflection. So, can anyone help me? I'm looking to =
>information on the following.
>
>Q1.  When drilling .008 to .010" diameter holes in say a .021 thick =
>panel, what is the best ( and available ) flute length? We=20
>        have concluded that  we want the flute length to be as short
>as =
>possible to minimize deflection but obviously long=20
>        enough to penetrate the panel. Were just not sure yet how much
>=
>longer.
>
>Q2.  What are other peoples experiences in drill wonder on small
>drills. =
>REAL NUMBERS PLEASE!  Case studies=20
>        performed  under ideal controlled conditions do not really =
>represent what happens in production. I am interested in what=20
>        people are seeing on production panels.=20
>
>Any help is appreciated.
>
>Ed Cosper
>Director, Quality Assurance and Engineering
>Graphic Electronics Inc.
>
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