If you ever need to drill an acrylic tank....

[Anonymous]

http://www.harborfreight.com/cpi/ctaf/D ... mber=39811

Really low price for all you will ever need. Keep in mind my local TAP plastics sells these bits for cutting acrylic at 15-25 a piece, this is a 16 piece set for $30 bucks! It's also the only way I could find a 1.75" Forstner bit.

 

[liquid]

Not a bad find at all.

One bit I've always liked for drilling PVC, acrylic, etc has been a Unibit:

http://www.harborfreight.com/cpi/ctaf/D ... umber=5751

Shane

 

[PeeJ]

how exactly does that work?

 

[hdtran]

I personally would not use Forstners or the Unibit for large holes in acrylic sheet. You're trying to remove way too much material, on a material which, frankly, cuts like crap (brittle, melts, gums up cutting edge, etc.). I would (and have) used hole saws. If you're shopping Harbor Freight, try

http://www.harborfreight.com/cpi/ctaf/D ... mber=38425

Do double check to make sure that item has the diameter you need 8)

Drill a small pilot hole in the acrylic (say 1/8") to pilot your pilot bit for the hole saw (try saying that quickly 5 times in a row ), then, start your hole on one side; go to the other side and start a hole too, to prevent chipout when you break through, then, drill through. If you're being utterly paranoid, clamp a backing board on your tank too.

You'll be left with a reasonably nice hole, and an acrylic donut. Not a whole (hole?) ton of chipped edges to clean up, nor too many messy acrylic stringy chips.

I've never used a Forstner on acrylic, but I would bet that you'd have an awful lot of melted gunk if you did.

That said, I like Forstners for making pockets in wood.

 

[Anonymous]

I second the unibit for THIN acrylic. You can stretch the hole up to the size you need. Provided the sheet isn't thicker than the graduations on the bit. If it is thicker, you end up with chamfered (sp?) holes. I just go slow and make sure the bit cuts(rather than Rips) the hole.

And I use hole saws (and water) for anything over 1"

B

 

[Anonymous]

I asked my local TAP plastics what they use to cut their plastic, and they told me they use Forstner bits, high RPM, and low pressure. I've used hole saws before, and they chew up the acrylic.

 

[PilotNY]

Keep in mind 2 things when drilling plastic. Keep coolant on the cutting bit ( so you don't melt the plastic) and ALWAYS wash out what you just drilled (to remove the coolant). I had a friend who cut out holes for a bulkhead and forgot to wash his new fuge. Put in online and boy did he have trouble for several weeks until he removed the fuge and cleaned it out several times.
FWIW

Carl

 

[hdtran]

When I used to live in No.Cal. (admittedly, ages ago), Tap in MtnView told me to use a hole saw.

Maybe a Forstner in a drill press, a machine tool, or with someone with good hand-eye coordination (definitely not me 8) !!) would have better results.

 

[taikonaut]

Forstner is for drilling a hole with flat bottom. For drilling the panel all the way thru, it is a waste of time to use it.

 

[John_Brandt]

I have drilled thousands of holes in acrylic. I've never used anything other than good quality hole saws (I use Milwaukee and DeWalt). I've never heard of using a coolant for drilling acrylic, and am strongly skeptical of this advice.

Use high speed and advance somewhat slowly. Never ever let off the trigger until the bit is completely pulled out of the hole.

 

[Anonymous]

Hmm, well I just cut two 1.75" holes for bulkheads using the Forstner bit. I sprayed it with a bit of water every few seconds as it seemed to be getting hot, but on the second one I didn't spray it. The plastic didn't gunk up or melt, but it did produce dust everywhere. I'm using a drill with (I think) 1500 RPM, the highest I could find at my hardware store. I've used hole saws on drill presses before, and it was a lot trickier than what I just did. I was using hole saws designed for wood, however. I've never been able to find hole saws specifically for acrylic locally.

BTW, here's TAP's site:
http://www.tapplastics.com/shop/categor ... 68292e9355

 

[DeChamp]

Forstner bits defenitly do a much nicer job! As far as melting the plastic I believe all the extra metal on the bit slows the heat obsorbtion down, so it take more to get it up to the melting point.

 

[Anonymous]

john brandt,
I use good ol' water as a coolant when I drill anything over 1/4. it just seems to make the hole cleaner when I'm done. That way there's no chemical residue left on the plastic. (like using antifreeze when drilling glass.)


B