Homebrew PCBs

Hello,

It works going the "other way" too. Using much STEEPER angles, then 
the breakthrough is a gradual thinng. Most drill sold fro plastic 
drilling will look like pencils; point wise.

Ballendo

--- In Homebrew_PCBs@yahoogroups.com, "Dave Mucha" <dave_mucha@y...> 
wrote:
> --- In Homebrew_PCBs@yahoogroups.com, dg140@f... wrote:
> > For larger holes in plexi, drilling a pilot or starter hole works 
> well;
> > speeds at about 500-600 RPM,; and the plexiglass bit with its 
> appropriate
> > flutes and sharpness.
> >
> 
> The key to drilling plastics is to drill with a flat bottom drill.  
> the normal taper drill will remove a lot of plastic and as it 
exits, 
> the area of contact suddenly gets much smaller and before you know 
> it, the flutes will grab and push thry, often cracking the part.
> 
> a flat bottom drill, like an end-mill will not suffer the same exit 
> problems.
> 
> Dave