Drilling Into Acrylic

I think you have to slow down the drilling or put another piece of material under the acrylic when drilling.

 

Buy drill bits that are specific for drilling into acrylic.

 

we just use standard bits for drilling steel, if your drilling like a 10mm hole start with a smaller bit and work up.

 

They make a plastic cutting drill bit that has a sharper point and less pitch than a conventional drill. I've also seen a suggestion for using like water or something while drilling so that you can keep the material from getting to hot and possibly melting. You will want to drill slowly to avoid stress cracking. Maybe practice these suggestions on a scrap piece to see if they work for you first to keep from ruining the project.

 

Use these and it won't crack. Do some test holes to get the speed and pressure correct. I used this exact set to do 3/8" standoff holes in 3/8" material and it went just fine. If you buy on amazon, don't just buy any old thing.. some of the reviews were not good on there. These were the only ones that had good reviews and I am one of them.

https://www.amazon.com/Plastic-plex...ords=acrylic+drill+bits&qid=1576012373&sr=8-5

 

A good read:

https://signs101.com/threads/best-drill-bit-for-acrylic-and-polycarbonate.121976/

I love the search function.

 

Bits for acrylic and Polycarbonate typically have a 60° tip.

I've drilled hundreds of holes in acrylic/poly and the step bits work the best (even better than bits intended for plastics, in my opinion). I use these from Harbor Freight and they work great. If you're not near a Harbor Freight, grab a cheap set off Amazon like these.

 

not a fan, but its possible to use regular steel drill bits. used/dull bits are actually better than brand-new ones. since the cracking comes as result of the sharp tip catching the acrylic and wanting to shove itself right-into it... attempting to split it rather than cutting/shearing.

So as stated above, start small work-up.
I actually do it with a twist: for larger bits, I drill in REVERSE!
Piloting with an 1/8" bit, drilling per usual, but then when I load up the 3/16">1/4">5/16">etc. bits, I throw my drill into reverse and "melt" the hole. sounds silly, but it works.

added tip: if you needed a 3/8" hole, like most standoff hardware, you'll want to have your final hole to be with a 7/16"-1/2" bit to allow for a little wiggle-room when installing. if you try to drill it exact, you'll always wind-up being just a little off when you go to hang the acrylic, and you can't just shove it in since tension + acrylic = potential disaster.

 

We use step drill too and never had a problem. Even if it is a newbie doing it.

 

+1 for strip drill bit, they work flawlessly.

 

I second that - we also use those bits and they are great along with the tip to clamp to a solid sacrificial piece when drilling.

 

Lennox Unibit, or sandwich between two pieces of pvc clamped with a Kant Twist.

 

material underneath and on top, you don't have to clamp them, but pressure them together and a nice new bit

 

I agree you don't have to clamp them, but, when instructing my guys I always tell them to clamp it. All it takes is a little less pressure on hole number 4 and bang, the hole gets blown out. The kant twist is a great little clamp that has very fine control of the clamping force and it's spread across a 1x1 copper cube, so you don't have the same risks as a c clamp or the awkwardness of the 'squeeze clamps' or whatever you call that pistol grip joke of a clamp.

 

ooorrrrrrr you could just use the correct bit.

 

I think the real answer is, "why didn't the CNC guy make the holes for you!"
I'll get some of these bits though. Honestly never tried anything like it except for unibits.

 

I don't have any "my guys"....

the silence can be beautiful and deafening