Homebrew PCBs

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