> 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.
>
> --Chuck
Agree with Chuck, a moderate drilling speed is better, you do _not_ want
to melt your way through, you want to cut.
And my advice, sadly learnt and forgotten quite a few times, always after
drilling a critical part:
**** CLAMP THE JOB DOWN! ****
If you think you can hold the Perspex with your fingers, you can't and
your nice panel piece suddenly catches, climbs up the drill bit in a flash
and is wrecked before you can say something nice like 'Oh golly I do wish
I had clamped it down!' or words (not) to that effect.
For clamps I suggest those newfangled ratchet clamps. I bought some a few years
ago and they are the best thing ever. These things ar esuperior to the
average old-fashioned G-clamp in almost every way, except for when massive
pressure is required. (search 'crescent connect clamp' on eBay, the 12" ones
are excellent). And like G-clamps, you can never have enough of these, get
some different sizes.
Steve.
