Drilling Plexiglass

[kangoo]

Hi,

I have been trying to drill through plexiglass with a 9/32 ( thats about 8mm ) multipurpose drill bit. But it binds when I try to drill and gets stuck, cracking the plexi in the process. I also tried drilling a pilot hole first but I still get the same problem.

Are there speical plexiglass drill bits ? I couldn't find any at regular hardware stores

Do I need a Uniblitz bit ? Because they are quite expensive if they won't work

Or should I do incrementing size pilot holes ? which is basically the same as using a uniblitz

Any other suggestions ?

Thanks

[Jidis]

Kangoo,

It shouldn't do that, and I don't think there are special bits. There may be ones with certain rake angles which are better for that purpose than others (sort of like the metal bits), but if you're using a fairly sharp new bit, it should cut through. The plastic should swirl out of the cut in a long spiral shaped sliver.

My problems with it are the exact opposite. It tends to goo up from the heat, even if I slow the drill down to minimum. I usually take out a little, and back the bit out so it can cool down and the hot trash can fly off, and then take a little more until I'm through. Drilling is actually one of the easier, due to the slow speeds.

-George

FWIW- I'm using a small press. If you're going by hand, make sure you keep a nice perpendicular angle and don't press too hard. I guess the smaller "pilot hole" techniques for larger holes also apply to plexi.

[Screaming_Rabbit]

I will soon do some drilling in plexglass again. It's about 15 years ago since I did it the last time and I remember having some trouble too.

I remember that I made good experiences with high speed rpm while using a drop of oil. Make shure, it's an oil which doesn't react with the plexi. Normally regular household oils like for oiling door angles will do. You can also try cooling the drill bit with pressured air.

If the drill bit gets stuck because melted plexi, apply pressure on the drill in intervals so the drill material has time to transport the heat energy away  from the drill point.

Greets, Roger

[kangoo]

Thanks For the advice :)

I didn't take the speed of the drill into acount. I switched to a bigger drill that I borrowed from someone, and I also used bigger better clamps to attach the workpiece to my "workbench" (aka the kitchen table, lol) and sucess !!!  Nice clean drill holes without the need for pilot holes.

Actually on a second attempt I discovered the my drill was powerful enough and that good clamping is a must for bigger holes, in fact even smaller holes turn out better on a well clamped piece.

This is what I have learned :

Drilling Plexiglass without a drill press

1. Use a center punch to mark the location and to avoid having the drill bit slide on the worksurface and ruin the material. (A must for drilling PCB's as well BTW)

2. Adequately clamp your workpiece to the workbench. In my case, my workbench is the kitchen table, I clamped the Plexiglass to a piece of scrap wood  so I don't make a hole in my table (and  upset  your roomate, significant other, or mother !!). Then I clamp the scrap wood tightly to the table.

3. Drill, using a fairly high speed (I pressed the trigger about 1/2 to 3/4 of the way on my drill).

You can make a pilot hole as well, but I found it un-necessary. unless you need to make a lot of bigger holes,you may want to consider it. I have found that drilling many holes can become monotenous (??spell check), after a while you make become either overconfident and/or sloppy. A bigger drill bit has a better chance of slidding off the center mark and ruining your workpiece.

PS: The scrapwood I'm using is aromatic cedar. When cut or drilled it produces a nice soothing smell which will make you driling experience more enjoyable !!

[Steven_C]

kangoo, I'm glad you found a solution that works for you.

Just another tip... I have found that putting a tiny bevel ground on the leading cutting edge of the drill bit makes it much easier when drilling perspex. This stops the drill from pulling into the material. High speed helps too. (this comes from experience of drilling hundreds, maybe thousands of holes in perspex) I'm not sure how similar plexiglass is to perspex though.

...Steve

[Jidis]

Yeah, I was reading some stuff on it last night. There's actually a bit specifically for plexi, which may be ground like that, but I've done alright with sharp cheap ones. In woodworking, I've had to resort to the high speeds when my bits weren't sharp enough. It creates more of a smooth "grinding" of a hole, rather than shaving the material out. Unlike Norm Abram, I keep a full arsenal of dull bits. ;)

Most of the stuff did seem to recommend the slower speeds and Kangoo's finding on the support piece was emphasized as well. There was also a tip about getting cleaner holes by drilling most of the way through and then flipping the piece to finish the hole from the opposite side.

It can also apparently be bent around corners with a heat gun (could be interesting).

-George

[Screaming_Rabbit]

It can also apparently be bent around corners with a heat gun (could be interesting).

... yepp... that's just what I'm doing this Sunday evening. I'll buil a "snap-in" holder for my portable GPS, to clip it to the middle console of my car.

Greets, Roger

[Jidis]

Roger, you've been watching too much "Night Rider" ;D

-George

PS- There's cool looking gloss black plexi around too. I've got a chunk that I scavenged off the door of a dead dishwasher.

[Screaming_Rabbit]

Roger, you've been watching too much "Night Rider" ;D

-George

PS- There's cool looking gloss black plexi around too. I've got a chunk that I scavenged off the door of a dead dishwasher.

I lately just bought a big sheet of this black plexi a couple of days ago  ;). Actually I bought it for some finishing parts for my LC, I'm building

Greets, Roger

[SounDuke]

Hi,

I'm using a material which looks like Plexiglass, but more flexible. It is a polycarbonate, a chemical composed of dyphenol which is very easy to work. Its commercial name is Lexan (it has different names depending bythe distributor).

[Jidis]

Yeah, Lexan's the common one here too. I think I've got some of each, but it's mostly Lexan.

-Good stuff!

[Fx3_hdrive]

polycarbonate

hmmmm isnt that what apple makes their ibooks from?

it sure is lovely  ;D

[Twin-X]

You get the best results by doing the following.

Create mark point

Set drill in HI speed

Set drill in reverse

Do not be disturbed by plastic melting back on. After drilling you can scrape it off easy