Homebrew PCBs

Chris,

Elegantly simple! You get a very clear view of the place to be drilled and
quick action.

I sounds like it doesn't take long to develop the skill to make this work. I
have plenty of 0.75 mm drills to learn on ;-)

I'm confused about the pulley's role. Is the 3' rod resting on the pulley or
is there a rope attached to the pulley that supports the rod? 

Rick

-----Original Message-----
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of chris
Sent: Sunday, January 13, 2013 7:00 AM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Re: What size drill bits?



--- In Homebrew_PCBs@yahoogroups.com, Mitch Davis  wrote:
>
> On Sun, Jan 13, 2013 at 10:59 AM, thb201  wrote:
> > I was looking to get some drill bits but I only want to get just a 
> >few sizes, especially if I spring for the more expensive carbide types.
> 
> Carbide bits stay sharp for a long time, but they are amazingly 
> brittle.  The slightest sideways movement and *ping*, they're gone.
> It's not realistic to use them with something you hold in your hand.
> I have used a normal drill press with good results.
> 
> Mitch.
>

I use 0.8mm carbide bits in a hand held proxxon

I can usually manage a few thousand holes before the drill breaks..

My wife usually breaks the drill withing the first dozen holes or so..

I have been through several methods of drilling, including a commercial
drill press,  a home made foot operated drill press, a CNC drilling machine
and ended up with the following

a pulley at ceiling height

a proxxon hand held drill fittted to about a 3 foot aluminium pole

the pole is suspended from the pulley with a counterweight giving it
slightly negative weight so that when you let go it goes upward, away from
the board

the very end part of the proxxon has a rubber grommet fitted..  and it it
this that is held lightly between finger and thumb..

this setup keeps the holes vertical and reduces hand and arm strain..

using this, my wife can drill almost as many holes as I can before breaking
the bit..

I manage about 2 holes a second when they are close together..
with an average of about 1 per second over a longer period

thats a fair bit faster than my CNC machine can do.. when things like
clamping and regictration are included.

Chris





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