Routing acrylic

[CoryBee]

How should I cut and drill acrylic for a small panel? I figure i could cut the acrylic to a rectangle, sandwich over the panel and flush trim it to perfection. For the holes I was wondering if I should use a spade bit like I have been which takes time cause you need to go slower or use a flush trim bit on it after I drill the holes in the wood.

Any help is welcomed, I would rather not buy new tools if the ones I have can do it, albeit a bit slower. Thanks 

[Venomouse]

Brother and I used a fine jigsaw blade and spade bits, the tip is with the spade bit drill from the side thats the top, and go slow.

[selfie]

Use a smaller spade bit then flush trim to finish

Read this any other Q's just ask

[gamepimp]

I had zero luck drilling acrylic (plexiglas) and actually ruined a very expensive piece trying to do that. So what I ended up doing was taking a straight cutting router bit (the kind that u can plunge down into material and cut a slot or remove material) and plunging it down thru the plastic to make a hole. I held the router at an angle so that the bit would gradually cut thru the material. The bit was 1/2" diameter, so that gave me a good hole to put the flush trim bit thru so I could remove the rest of the material to the exact size of the hole. Worked like a charm. Btw I used a laminate router to make the initial hole. It was easy to start the hole at an angle due to the small size of the router. Doing it with a full size router might b more of a challenge. But maybe a plunge router could be used to go straight thru slowly?

[yaksplat]

here's my process (over a dozen panels and not a crack yet)

1.) Build and Drill panel
2.) clamp plexi to the panel
3.) mark all holes with a black marker in the center of each
4.) write 'UP' on the panel so i know which side faces up
5.) remove clamps
6.) On drill press, use a 5/8" forstner bit (ordinary drill will work too)
7.) drill holes on all the marks, making sure the back of the plexi is always supported
8.) reclamp the plexi to the CP, making sure that 'UP' is facing up and that all holes are roughly centered in their respective locations
9.) rout the outer edge using a 1/2" flush bit at high speed, moving clamps where necessary
10.) rout all of the button holes

if the panel contains a happ trackball mounting plate:
1.) Mount the plate on the panel
2.) Use the above process but rout the trackball hole within around 1/8" of the metal plate (router bit + metal = bad!)
3.) Clamp the CP and plexi in a bench vise vertically
3.) Using a drum sander attachment in a drill, the remaining plexi is sanded off up to the metal edge

Hope that Helps! 

[Seith]

Here's what I did to not only cut my acrylic, but to also cut an identical template board if I ever needed to recreate my control panel in the future:



From bottom to top:  Original Control panel top, plexi, board which will become my template

Run your flush trim bit around that to get the shape, and you come out with this:





Now, I used hole saw bits instead of spade bits after reading on here that people have had bad experiences with spade bits cracking plexi no matter how slow they went.  I took a test piece of MDF and drilled it, just to see how the hole would come out:





As you can see, there's quite a bit of blowout on the bottom, so I sandwiched a piece of particle board to the bottom of my rig:



I went to drill using the hole saw bit and came out with this:





L to R:  Control panel, plexiglass, template panel

I also got a 45 degree chamfer bit for my router and did the trackball lip:





Hope that helps!

[CoryBee]

Nice guys, nice. Couldn't have asked for a better answer than what you guys gave. Bookmarking for future use for sure. I like the idea of making a template at the same time.

Yaksplat, you are a genius. Or just really nice for making that step by step mini guide, will be doing this only a little different. No drill press, but i can drill pilot holes for sure than finish out with the flush trim bit. 

[selfie]

From my Working with plastics thread

Drilling

I've heard some interesting methods for drilling plastics over the years. Running bits in reverse is a common one but I remember my high school shop teacher taught the "Correct" way to do it was to blunten the drill bit on the concrete floor before drilling plastics.

The key to cutting clean holes is to scrape not cut. Any standard twist drill can be sharpened to cut acrylic by taking the leading edge off the cutting surface.



Spade bits like this can be resharpened to scrape not cut and used

but NOT spade bits with the points like this


Forstner Bits and hole sawsare suitable also


When drilling thicker material start with a small pilot hole and drill half the thickness from both sides and never use a lot of force.

[yaksplat]

Anytime you drill, you should always have a backer piece on whatever you're drilling.  This will eliminate all tearout from the back side.  I have several scraps that I use solely as drill backers that are covered with dril marks.  You don't have to worry about this as much with hardwoods, but definitely on plywoods and particle boards.

I don't agree with the melting instead of cutting for plastics.  As long as the plastic is supported, the bit is sharp and the pressure is even, you will get a perfect hole every time.  Using my drill press, I apply a lot of pressure on the bit and it cuts wonderful spirals of plastic.  With metal working the theory is 'more feed, less speed' for good cutting practice.  I've found that this works for plastic as well.

[wcndave]

Some confusion on terms as well.  this is a holesaw



What Selfie posted a picture of and Self demonstrated blowout with are Forstner bits.

[rbarr110]

How should I cut and drill acrylic for a small panel? I figure i could cut the acrylic to a rectangle, sandwich over the panel and flush trim it to perfection. For the holes I was wondering if I should use a spade bit like I have been which takes time cause you need to go slower or use a flush trim bit on it after I drill the holes in the wood.

Any help is welcomed, I would rather not buy new tools if the ones I have can do it, albeit a bit slower. Thanks 

I recommend using cast acrylic as it machines/cuts much better.  The cast acrylic usually has the paper backing that you peel off (not a clear film that is peeled off).  I use my CNC to cut cast acrylic and have ZERO problems cutting it.  When I had previously used extruded acrylic, it cracked easily when I tried to drill/cut it.