> On Oct 27, 2015, at 12:33 PM, Jon Elson <el...@pico-systems.com> wrote:
>
> On 10/26/2015 11:38 PM, Chuck Guzis wrote:
>> On 10/26/2015 08:54 PM, wulfman wrote:
>>> To effectively drill in plastics you need to run the drill press on
>>> the highest speed you can and use a freshly sharpened drill bit.
>>
>> If this is Perspex/Plexiglas, I've had great results with a good sharp
>> Forstner bit in my drill press at medium (say 750 RPM) speed and a not-too
>> aggressive feed.. No melting, just lots of crumbly shavings. I've done this
>> with sizes down to about 1/4", but no smaller. When you're almost through
>> the material, turn it over and complete the hole from the back side. Very
>> clean edges, with no chips at all
> The ultimate way to drill holes in Plexi is with an end mill. It can make a
> slight chipping when it punches through the back, so you either need a
> backstop material or lighten up the feed a bit just before it goes through.
> (This of course requires a center-cutting end mill, I prefer 4-flute for
> this.)
I would think a counterbore would work better, because it doesn't cut on the
sides, only on the bottom.
paul
