Special Bit for Drilling Plastic?

[loans_n_fishes]

I have some of those specimen containers that I want to drill for a "hang in" refugium. Do I need to use a specific drill bit to keep it from cracking?

[hobogato]

paddle bits seem to work a little better with plastic. if it is a large hole, you can drill a small hole and then enlarge it with a grinding bit on a dremmel tool.

[Ping]

A forsner bit is probably the best but a hole saw bit will work also. The key is to go slow. Maybe Ace will see this and know more.

[hobogato]

oh yeah peter, didnt think about a hole saw - guess it just depends on the size of the hole you are drilling.

[Ping]

we posted at the same time.

[loans_n_fishes]

So, a paddle bit is the kind that look like a flathead screwdriver? Forgive my naiveity. :blush

They will be small holes (1/4" to 1/2" diameter).

[hobogato]

yes, and that is what i would use for a 1/4" hole - just go slow. for 1/2", you could use a hole saw or drill a 1/4" hole and then dremmel it larger. that's what i would do anyway.

[prof]

You can use a spiral drill bit but you have to file the edges. Spiral bits are designed to grab the material and pull themselves in. If you don't file the edges down it will grab acrylic and pull it up, usually cracking it.

Go slow and use a drill press if you can.

[erick]

A step bit works real well too. Drill a small hole and then use the step bit to enlarge it, no rough edges or anything, makes perfect enlargements. BTW, a step bit goes from a small diameter to larger ones, looks sort of like a cone, IMO no tool box should be w/o one....

[Headless_donkey]

Second on the step bit and going slow!

[erikharrison]

who here in SA does Acrylic work on a daily basis ? Just curious...

[hobogato]

depends on the week :)

[erikharrison]

hey Ace do you know why the time is out of whack on this site?

[erikharrison]

blah it double posted

[caferacermike]

For small holes in thin work I'd go for the step bit. For large holes I'd shoot for a holesaw, not to mention if you run them in reverse they work just as well but do not crack the work piece. Not to mention I have several step bits if you need to drill something. You know where the house is if you want to schedule a time to drop by and drill those holes.

[aprilmayjune]

You can also use those plastic boxes that are for isolating breeder fish. You do have to break off the floater boxes on the side, but they already come with small slits around the sides for waterflow.

[matt]

Here's how I drill holes in acrylic. For small holes, like for a nylon bolt, i have a couple of spiral bits that are designed for acrylic; most plastic stores will have them. They work pretty well; regular wood bits work okay if you go slow. I never tried a flat wood bit. For larger holes, I find something that I can use as a template; this could be either the inside of a PVC fitting, or a hole drilled in a piece of plywood or scrap acrylic with a hole saw. (I never use a hole saw on acrylic I'm planning on using in a project, as the heat generated by them is bad for the acrylic) Then once I have the template, I use double sided tape to fasten it on the acrylci, exactly where I want the hole, then drill a small pilot hole, then use a router with a flush trim bit to rout out the hole; the bearing on the bit rides along the template. It works perfect; it's extra work for the first time, but once you have the template it's fast and the quality is great. The best thing is that the plastic does not get hot when you're drilling, which is very important if the area is going to be under some stress or get solvent welded.

I used to do acrylic work almost every day, but I've been too busy with my real life (such as it is) to do much in the last few years.