Drilling Holes In Acrylic?

[GoodWood]

I got a new Dremel 330 router base for inlay/rosette work. the center hole thing it comes with measeures 2.25 inches from center, so I have to adjust this to 2" for center holes. The base is acrylic, I may just mount a separate acrylic base to this with the hole in it, but Id like to to be somewhat adjustable,a nd I had bad luck with acrylic cracking a few times. Is there any tricks out there to cutting / drilling clear acrylic?

Thanks

[thegarehanman]

Use lexan instead of acrylic, you'll find it to be much more workable and well worth the slightly increased cost.

[davee5]

To add to Russ' comments. For this application clear polycarbonate would probably be better to work with. It's easier to machine and tougher than acrylic, so it will last longer too.

However it should be noted that acrylic is much harder than pc. While it cracks & crazes more easily as a result, it also scratches less easily. If you aren't careful with that polycarb base you might ding it up easily and then inadvertently scratch your wood when using it to route with as a result of the burrs. You ever see a PC nalgene bottle owned by someone who really loves the outdoors? They look terrible, absolutely beat to hell, but they take abuse. But while they still hold water you'd never want to drag that dinged & scratched up bottle over your nice wood. Just food for thought.

If you decide you'd like to stick to acrylinc the answer to your problems is to use a drill press, sharp tools, and fast cutting speeds (low chipload). If you drill by hand, especially with an old & dull jobbers-twist bit, you'll almost certainly cause the bit to bind and catch a chip, which will crack the acrylic. Using a drill press keeps the depth much steadier and prevents the gouging you are at much higher risk for when drilling freehand. Often drill presses will also run much faster spindle speeds, which will also help. If you must drill by hand, don't push so hard, use a new or recently sharpened bit, and keep it spinning real real fast. Acrylic, like PC, actually drills pretty easily if you're nice to it.

Lastly if you really want to do it right, use a bit of coolant like rubbing alcohol right on the dutting surface. Just dab some on teh plastic before you cut, then occasionally as you "peck" the bit through the material put a bit more in the drilled hole. Better resultant surface finish, happier tools with longer lives, and less chance of binding due to thermal expansion.

-Dave

Edited February 13, 2007 by davee5

[GoodWood]

Cool, thanks. Fingers crossed

[GoodWood]

I ended up cutting a small notches out with a bandsaw, then I used the Fordom tool and carved out a half moon. It was soft stuff, not sure its acrylic. I will now use a center nail and secure it with Friendly plastic. Ill do a pic when its done. Looks like it will work.