Homebrew PCBs

--- 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