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Subject: Re: [Homebrew_PCBs] Re: Copper Foils

From: dhlocker@...
Date: 2008-12-22

Q: Why is bottom posting evil?

A: Because it makes people who have been following the thread reread the entirety of it just to get to the two-line ME TOO buried at the bottom.

Donald.
Who actually thinks in Reverse Polish, and for whom top posting is as natural as breathing. If you prefer bottom-posting and bottom-reading, suit yourself, but don't try to make me reprogram my brain. After 56.5 years, I don't think it will happen. But I won't try to make you change either. Now, David, let's get back on topic.

-------------- Original message ----------------------
From: David Griffith <dgriffi@...>
> On Sat, 20 Dec 2008, William Alford wrote:
>
> > At 01:29 PM 12/19/2008, you wrote:
> >> Does anyone know if I would get away with drilling glass with a
> >> standard tungsten carbide drill bit set. The spindle speed of my mill
> >> goes up to 60krpm.
> >
> > i've drilled glass and ceramic tile and stone. you need to drill
> > ∗slowly∗. and spray repeatedly with water to keep cool and remove
> > residue. i've used tungsten carbide bits (can get at home depot in a
> > few sizes) and they do work but have a short lifetime. i got about 6
> > - 10 holes per bit before wearing out. most of my drilling was in
> > 1/4" glass and granite, so i don't know what thickness you intend.
> > diamond bits are better, but still require water to last.
>
> I have a book somewhere that describes making a drill bit by mounting a
> copper or brass tube on a steel mandrel. Cut two V-shaped notches in the
> business end. A clay dam is built up around where the hole will go.
> Pour an abrasive slurry in there and carefully lower the drill. Top up
> with water/slurry as needed.
>
> --
> David Griffith
> dgriffi@...
>
> A: Because it fouls the order in which people normally read text.
> Q: Why is top-posting such a bad thing?
> A: Top-posting.
> Q: What is the most annoying thing in e-mail?