Light Desk

I really wanted a light box for all the drawing I do. Specifically for a massive drawing I was working on.
So naturally I got completely side tracked on this project instead of just finishing said drawing.

The brief was pretty simple.
1. Large
2. Adjustable table angle.
3. Light box table top.

Most of the design work I do is in acrylic but this is the first time I've had a go myself.
Thought it would be good to break away from the usual metal fab stuff.

So this has been designed in a combination of 10mm opal acrylic and 6mm frosted translucent red acrylic.
10mm acrylic by itself is too flexible for most of the parts on the desk and going up to say 20mm can be expensive.
I got the sheet of red acrylic for nothing so I used that in conjunction with 10mm stuff to create this multi-layered design.
With the red acrylic being free I could get the required thickness for a stable desk without having to spend the extra money on the thicker opal acrylic.

The only metal fabrication needed was for the cross supports, in aluminium tube.
The rest was very very simple, all the holes required were laser cut. All I had to do was tap threads, countersink holes then screw together. Except the light box underneath  which required a bit more in the way of plastic fabrication.

Step 1. Have an idea,
Step 2. Click clack the keyboard and mouse till it looks like what you want.
I did this in 3D obviously. These are renders of the major parts.
The main reason I went for CAD to design this is my pencil does not have an export to dxf function.

Before anyone asks I'm not intending to upload any of the files for this thing.
The whole reason I design and make stuff like this is for myself is because at the end
I (usually) have a product that suits my exact purposes with my own style too.
I always encourage people to have a shot themselves, you'll always be happier
when at the end of a build it is your vision that has become a reality.

Make sure you have a steady hand when you are laser cutting. Jokes.

It is so great these days that laser cutting is available to even hobbyists at a reasonable price.
I used a local laser cutting place, the one we use at work.
Whilst the online services are very convenient, click some buttons then shipped to your door I find them more expensive
than using local laser cutting businesses.

Once you have all your parts organized you can lay them out on your "sheets" virtually.
This operation is referred  to as "nesting" your parts.

The top sheet is the 10mm opal and the bottom is the 6mm red acrylic.
This was just a loose nest to see how much acrylic I would need.
Most laser cutting business will have specialized software that will automatically nest parts
to minimize wastage and reduce laser cutting time.

After a few days wait my pallet of bits arrived.

I used M6 countersunk socket screws to put this together.

All the holes were part of the laser cutting process. So all I had to do was tap the base parts (the opal acrylic)
with an M6 tap then counter sink all the other holes on the secondary parts ( the red acrylic).

5mm diameter holes are needed to tap an M6X1mm thread. I usually set holes I'm going to tap in the laser cutting file
a little bit smaller than I need, say minus 0.2mm. Set at the correct size they end up a little bigger than 5mm.

You can use a hand tap like pictured below but if you have a ton of holes to do it's probably too slow.
I just used a power drill with the clutch setting on low.

For the three support tubes that connect the sides together I used 40mm diameter aluminium tube, 3mm wall.
I used a hole saw to make 6 6mm thick discs to blank the ends off and tapped an M10 thread in the centre of them.

I TIG welded the blanks on to the end of the tubes (image below). This was the test piece to set up the welder.

The top tube also acts a the pivot point for the adjustable table angle.

You can see in the first pic the range of motion for the table angle adjustment.
The top tube acts as the pivot and the arm on the table top acts as the table support
with a radius slot as the guide.

A bolt and knob tensioner holds the two in place at the desired angle.
I routed a hexagonal hole half way in to the thickness of the red acrylic piece then glued the white piece over the top to hold the bolt in.
Sorry forgot to take a photo of the bolt head hole before  I glued the two together.

There is also a secondary guide spacer that sits in the slot in the red acrylic.
A tapped hole is in the main leg to take the bolt for the tensioner.

Like I said 99% of this is held together with M6 bolts.
Pretty self explanitory this step, put all the bolts together.
I think there is about 30 odd in each side.

The only serious plastic fabrication I had to do was the curved parts on the light box.

I made this simple jig out of a piece of scrap aluminium, bent over a piece of pipe.
I also drilled and tapped a few holes for a clamp at one end to hold the piece of acrylic.

Preheated the oven (not the kitchen oven kids) to about 300 degrees, took about 10 or so minutes till the pieces became soft.

I clamped the pieces in put them in the oven then when they were soft enough I pulled them around the jig, clamping the other side down with some spring clamps.

These glued the laser cut edges to form a box that glues to the underside of the tabletop.
The tray with the LED lighting screws to the underside of this.

To light the table I used LED strip lights on a red acrylic tray.
These are a flexible strip with an adhesive tape on the back, you buy it on a roll.
It comes in different colours and LED units per metre, I used 60 lights per metre
I used about 11 metres, only 5m is shown in the photos, I added a few more strips later on.

The LEDs are powered by a 12 volt 60w transformer.

There is a cut point every 5 LEDs so you can cut it to the length you want.
Each side of the cut point there are surface contacts you can solder to.
It's just a matter of soldering wires to these contacts then connect them to the transformer.
Make sure you positive wires go the positive terminal and the same for the negative terminal.

So here it is, works as intended so I was happy

Forgot to mention the square cutouts in the table top are for my pen holders.