Make a cheap box;
Sometimes you try to save some money, but you get stuck trying to find a metal box to put your project into. You look at electronics supply stores and see that pre-made metal boxes are expensive and you really don't need anything too fancy. This has been my problem for years, but I found an easy solution - I use some wood, screws and steel from the hardware store and the next thing you know, I have a box to install things in.
I don't know what is used in other parts of the world to build houses with, but a 2X4 in the USA and Canada is approximately 37mm X 87mm and 2.5 meters long.
Obviously, you can use any strong wood that you have available, so use what you have. I often have scrap lengths of wood that I use, however a 2X4 is usually pretty cheap in any store that sells lumber. I have even used Oak and finished it nicely in the past, however the great majority of boxes I build are made of left over material (cheap) and put together with what I have available.
The first thing I do is figure out how big the box needs to be (In this case, any switches or connectors will be mounted only to the top - so this is what I work out the space for). I'll often draw this to scale on a piece of graph paper and then measure it. When you do this, you end up with an X side (horizonal) and a Y side (vertical). I always like to add an extra 1/2 inch (approx 12 to 13 mm) to allow me a bit of extra room inside the box.
Here is how I lay out the 4 sides:
Notice that I measure the X and Y lengths, but I also need to know how wide the box is including the wood (thats where the I add 2 times the thickness of the wood to the X and Y lengths).
Now that I have that layed out and made, I go to the hardware store and buy a piece of steel - they sell small pieces in a number of thicknesses. Often, you will want a 16 gauge (approx 1.0 to 1.5 mm) thick piece - These are available in a number of sizes and while moderately expensive, but much cheaper than a pre-fabricated steel box.
Steel is not easy to cut and make it look nice. If you have power tools available, it can be cut to size with a Band-Saw, A Power Jig-Saw, or (my personal favorite) a metal cutting abrasive disk mounted in a circular saw (things get very hot with this setup, but its pretty fast). Cutting by hand saw will take a very long time. If you get your steel from a metal shop, they have tools that can cut it neat and clean, but will probably charge you more than you paid for the steel in the first place per cut.
You will want to cut the steel top to the size of the outside of the wooden box. I also drill a number of holes in the top that align with the center of the wood that it will be screwed on to, as such:
I usually only use steel on the top, leaving the back either open, or using 1/8 inch thick (approximately 6 mm) pressed board (also called Masonite) to close up the back with. I add rubber feet in each corner of the bottom of the box. Make sure that any holes in the top (or bottom) will not be in the same place as a screw that is holding the sides together.
When I decide to cut openings in the top (steel cover), I put it on the wooden box, then trace around the inside with a pencil so that when I take the top cover off to work on it, I will know where the wood is, allowing me to avoid installing something in the wrong place. I like things with round holes because these are easy to do with a powered drill (I use my small drill press).
Once you have cleaned up the sides of the holes and filed the edges of the top so that there are no sharp places, you are ready to give the steel top a coat of paint. Steel will rust, so I like to use a good grey primer paint and give it at least 2 coats and let it dry overnight. If you plan to gave a ground point at one of the holes, put a small piece of tape over that spot (on the backside of the top) so that you can connect to that spot and have a good bare metal connection. You may want to spray paint the wood sides too - its your option - it really is not important, unless you want it to look the same color as the top.
Thats about it. Once the paint is dry, install the top onto the wood sides, and then install the switches/connectors/lights or whatever you cut the holes for. If cables go thru the side of the box, pull it thru those holes now and make sure that you have enough inside the box to make your connections with. Once these are in, solder any wires to the parts. Test it and fix any problems.
I like Grey paint because you can write on it with a marking pen to label things, or you can print labels on your computer and stick them on. Do what works for you and be creative.
Let your imagination be your guide.
Questions? Comments? .
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