On Mon, 25 Apr 2005 18:58:55 +0200, Martin Haverland
<
professional@...> wrote:
>
>
>> I even drilled (and will drill in future) my single prototype pcb's
>> completely freehand with a dremel-like drilltool (hss drills).
While i agree with most of your post, HSS drills do not produce holes of
the same quality as carbide drills.
They get dull after a few and more like melt their way in than cut it.
(proof: your solderpin story)
This is however not a problem with many homebrew boards, and i think for a
beginner freehand drilling is perfectly acceptable, i have used it for
quite a while myself and as you say it is in fact faster than with a press
and carbide drills.
Note that sharpening the drill from time to time is a good idea, and it is
totally non-critical if you get it nice, in fact once i broke a drill
(yes, with HSS i only ever broke a single drill in a pcb, ever, and i did
that for years), well, once i broke one i just continued and the broken
edge drilled surprisingly well. it was more or less a straight break so i
think maybe holding it straight against a grinding wheel would work just
as well as normal sharpening.
Doublesided is possible, you can even correct very slightly for offset.
But note that the exit side has a even worse burr if there is copper than
the side where the drill enters.
ST