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Author Topic: Plastic project box cutting??  (Read 841 times)

KD2E

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Plastic project box cutting??
« on: February 08, 2022, 05:47:09 PM »

I have a plastic cabinet, that I'm going to cut some patterns, like for an IEC AC power connector on the back.
So what is best to accurately cut plastic?  Anything moving fast might melt it, too slow might crack it. Those vibrating things for trimming molding etc are too big and clumsy. There MUST be something slick and precise for this purpose??
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K7AAT

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Re: Plastic project box cutting??
« Reply #1 on: February 08, 2022, 06:43:56 PM »

I've used some small  router bits in my Dremel successfully on plastic....
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LA9XNA

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Re: Plastic project box cutting??
« Reply #2 on: February 08, 2022, 11:57:23 PM »

Look for a nibbler tool.
To get a good fit on the pattern you can print the footpint of the connector andglue it to the box with some water solutable glue (oat flour and water or just plain milk on th back of the paper) let the glue dry drill the hole and use the nibbler.

When working with plastics its important to have a sharp tool because this will give less friction and heating to melt the plastics. Dont overdo the RPM to get the job done  go at a slow speed and let the cutting tool cool down when its getting hot.

The type plastics is also important some plastics are more brittle than other. Boxes labled thermoplastics are usualy better.
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G8FXC

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Re: Plastic project box cutting??
« Reply #3 on: February 09, 2022, 12:43:15 AM »

I've used some small  router bits in my Dremel successfully on plastic....

I would tend towards a Dremel too - very versatile with a wide range of cutters and drills available. They are quite expensive - I have a real one at home where I do most of my construction, but I have a far cheaper unbranded one on our boat for odd jobs - it's not as well built, but it gets the job done too!

Martin (G8FXC)
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K1KP

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Re: Plastic project box cutting??
« Reply #4 on: February 09, 2022, 04:23:20 AM »

Google 'gourd saw'. These are very small powered jig saws that work really well for cutting plastic. You can cut very intricate shapes, and they have variable speed so you can avoid melting the plastic. Blades come with varying tooth pitches.

-Tony, K1KP
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W9AC

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Re: Plastic project box cutting??
« Reply #5 on: February 09, 2022, 04:30:26 AM »

Ditto on the Dremel tool.  A few weeks ago, I cut a square opening in a plastic project enclosure by using a thin cutting wheel attachment that came with the tool kit.  Keeping straight lines was somewhat difficult.  If there's a next-time, I'll use a section of angled aluminum as a straight edge.       

Paul, W9AC
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SWMAN

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Re: Plastic project box cutting??
« Reply #6 on: February 09, 2022, 07:36:12 AM »

 I tried the Nibbler tool in the past and it wanted to crack the plastic. If it was soft plastic it would have worked ok. But the hard brittle plastic just won’t cut well.
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W1VT

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Re: Plastic project box cutting??
« Reply #7 on: February 09, 2022, 09:10:47 AM »

The type of plastic makes a big difference.  Lucite or acrylic is preferred for clear or see through enclosures but it chips easily and is hard to machine.
Polycarbonate or Lexan is much easier to machine.  I've machined Lexan with an end mill in my milling machine.

It took a little practice but I was able to cut very nice rectangular holes using a milling machine.

Zak W1VT
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K6BSU

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Re: Plastic project box cutting??
« Reply #8 on: February 09, 2022, 11:02:50 AM »

Most power tools are too fast, and will generate heat that melts plastic.  I start with a small drilled hole and continue with round/square files.  Filing does not generate heat.
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W1VT

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Re: Plastic project box cutting??
« Reply #9 on: February 09, 2022, 11:36:18 AM »

My Sherline has a DC motor that generates a lot of torque at low speeds.  Great for working with plastic.
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K7LZR

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Re: Plastic project box cutting??
« Reply #10 on: February 09, 2022, 11:56:31 AM »

For round holes, I've had great luck with using wood cutting bits in my drill press. Speed is set such that it cuts fast without too much heating and I'm able to remove excess with a pocket knife.

For square holes, I use a nibbler for soft plastics such as ABS and a dremel tool if needed for harder plastics. Has worked well but I don't have much experience at it......
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WA3SKN

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Re: Plastic project box cutting??
« Reply #11 on: February 09, 2022, 12:25:54 PM »

This really depends on the plastic.  Is sounds like you want to do a nice clean job of it.  Have you looked at those "multi-tools" that are now on the market?

-Mike.
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VE3WI

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Re: Plastic project box cutting??
« Reply #12 on: February 09, 2022, 01:02:41 PM »

round holes:
For small holes I use a twist drill.  For bigger holes a Unibit is better.  Use a drill press at slow speed.  Clamp the work so it doesn't try to climb the bit.

rectangular holes:
I cut it a little undersize with a coping saw, then file to size.  You have to support it as the material cracks easily.

73
Dave, VE3WI
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KD2E

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Re: Plastic project box cutting??
« Reply #13 on: February 09, 2022, 01:28:53 PM »

Google 'gourd saw'. These are very small powered jig saws that work really well for cutting plastic. You can cut very intricate shapes, and they have variable speed so you can avoid melting the plastic. Blades come with varying tooth pitches.

-Tony, K1KP

That looks interesting!  And, it can come in handy around Halloween as well!!!
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WB8PFZ

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Re: Plastic project box cutting??
« Reply #14 on: February 10, 2022, 07:21:41 AM »

Find someone withe a 3d printer and make it with the hole in it :)
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