Stefan,
I have a Roper Whitney hand punch that i bought here in the UK if
that's what you mean... I wouldn't use it for pcbs though, a drill is
much easier. Where the punch scores is in thin sheet metalwork where
the drills tend to pull when they break through.
What I have found is that when drilling other than component holes in
pcbs, the best drills to use are the 'Bullet' type, they are easier to
centre on the hole, they do not bind and they break through more
cleanly...
I also tend to drill these holes with an old peice of MDF at the back.
I do have one board where the hole is 60 mm and for that I used to use
a hole saw. The two problems with the hole saw were a) hlding the
board as the saw grabs a good grip on the board. and b) having to
stop to get the scrap out from the centre of the saw every few holes.
I sorted a) by using another hole on the board dropping over a cut off
nail in the back board... and b) I now use the CNC mill to cut the
holes out with a slot mill.
Chris (-=Spiyda=-)
--- In
Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@...> wrote:
>
> On Wed, 08 Feb 2006 17:42:18 +0100, Jose Fuentes
> <josecarlosfuentes@...> wrote:
>
> > I am designing a board that will have two holes for
> >
> > screws. How can I place those holes in the PCB
> >
> > without using pads?
> >
> >
> > Regards
> >
> >
> > Jose
>
>
> I fear that depends on your software.
>
> Mine has a feature for placing holes, but it is basically only a pad
> (usually) without electrical signal.
> You can set copper diameter and drill diameter individually, if drill
> diameter is the same or larger there will be no copper ring around the
> hole.
> It should be possible to use a normal pad if your software doesn't
allow
> for special holes.
>
> As for producing the PCB, i will usually print with option "centering
> holes only" which reduces the size of all holes to what is useful in
> centering the drill. Then i'll drill there with some small drill i
use for
> other pads, and at the end enlarge the hole with the right size
drill. I
> want a hand puch for punching them holes for ages, but they don't
seem to
> find their way over the atlantic.
>
>
> ST
>