--- 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