Enclosure Design - How are people doing cutting square holes?

I am wanting to put my little arduino project into a nice little enclosure which will have 2 serial port connections, a usb connection and a RF connection on the rear of the enclosure. The front will have a couple of LEDS.

Now the front is no problem but the back connections are Square for the USB B port, and the 2 Serial are sort of Odd D Shaped .

So my real question is how do people manage to cut their enclosures to support their project without making huge mistakes?

How do I cut a square hole accurately? So it looks like a PRO job not something I hacked together.

The B connection is quite small only 11 x 13mm - so too small for a hacksaw.

I know a stupid question but for someone who has not done it before I think is a legitimate question.

Any tips appreciated.


I use a metal nibbler cutter. Drill a hole, then use the nibbler to square it off, then use a set of small hand files to finish.




See: http://forum.arduino.cc/index.php?topic=219747.0


We've used hydraulic hole cutters - you can get square punches.

Other than that, yeah that nibbler looks much cheaper.

And a file yes, I forget the term but try to get one with at least one blank face on the short sides, so when you cut, you're only filing one face at a time, easier to manage better results that way.

I use a CNC machine. Leo..

Thanks for the ideas.

I don't have a nibbler so I will try to find one at a good price in New Zealand.

A CNC machine would be great but I do not have one if those either.



Drill, file...

Cheap as chips.

Are you in AK?

I use a CNC machine.


1:1: Drill, file...

Cheap as chips.

Are you in AK?

No down in Christchurch.

There are some files which are rectangular. They have cutting surfaces on all four sides.

There is a version that only has cutting surfaces on parallel sides. Get this version. It will prevent cutting into the side of a hole while you are leveling out the top/bottom of the hole.


For an 11mm x 13mm hole, I would mark out the hole and it's centre, then after drilling a pilot hole, I would enlarge it to 11mm, and then just carefully file out the corners.

I'm now more likely to 3D print the enclosure with any apertures already in place - you can print holes at no extra cost!

One item that is worth its weight in gold is a optical centre punch

The workflow is like this

  • Draw your design using cad
  • print out 1:1
  • use spray stecil glue to tack the drawing to the metal or wood
  • use the optical centre punch to mark holes
  • for sraight lines or square holes use a suiatable saw and finich with a file

This gives you excellent precision

One item that is worth its weight in gold is a optical centre punch

Agreed, a bit expensive though. http://www.leevalley.com/en/wood/page.aspx?cat=1,180,42311&p=45502


I often see cases where the seam is aligned with the PCB, so the square "holes" just have to be notches, instead of holes.

If you don't have a milling machine (CNC or otherwise) or a 3d printer to print the case with the holes in it, I think you're stuck nibbling and filing.

I don’t have a 3D printer but have had cases with rectangular holes printed from http://www.makexyz.com/
They do design work too.

scottyjr: Show-off!!

Haha. Right.... Very proud of my machine. I have been using drills and files for the past 50years, and could finally afford one. Leo..

There is also:


And 'broaching'.

1:1: There is also:


And 'broaching'.