Not in FR4. If you use HSS in FR4 you drill the first 10 holes, and
you just friction melt them from that point on with a rounded stick.
The hole quality is bad with a blunt drill, burr on the top, large
burr on the bottom, and delamination from heat.
In phenolic paperboard i will believe it easily, but not FR4.
Been there, done that. By the way a HSS drill just broken off flat
drills PCBs almost as good as one with a proper tip at high speed. So
instead of re-grinding the tiny cutting edges just hold it end on
against the grinding wheel.
ST
On Feb 17, 2008 7:50 AM, Dylan Smith <dyls@...> wrote:
> On Sun, 17 Feb 2008 JanRwl@... wrote:
>
> > A HSS bit is perhaps flexible enough to tolerate hand-held drilling if you
> > are SUPER-careful and accurate, but it will DULL in FR-4 after two holes!
> > Carbide bits in a drill-press are the ONLY way to do it!
>
> I've done hundreds of holes with an 0.8mm HSS bit, they don't seem to dull
> _that_ quickly.
>