Here's a simple, small, cheap, yet effective tool to SAND and DIFFUSE your LEDs!

This one can actually be used for many other purposes other than sanding...

While it would have been nice to purchase a standard sander off the shelf, the issue of price as well as size proved prohibitive (as I needed it to sand just a few LEDs for my other project!)

I've added the pics of sanded and un-sanded LEDs for comparison...
I used LEDs with a wide viewing angle (120 degrees).

Step 1: What Do You Need?

Basically, You'll need a small DC motor (size really depends upon how big and powerful you want it to be!).
Also needed is a base to mount the motor over it and an extending shaft and some sort of a coupling mechanism to couple the the motor's shaft and the extending shaft. A 5g pack of Sugru should also come in handy.. Also needed would be a power supply (I used a switch mode adaptor) And off course you'll need somesand papersto diffuse the LEDs...
(Things Bold and Underlined are necessary! )

In case you happen to have a DIYMechanix (meccino) set as I did, you'll need the following:

RT-55 (The red base) - 01 pc.
BTB-5 (the L shaped brackets --- optional --- it might rattle a bit without them) - 02 pcs.
SH-3 (110mm shaft --- you can go with any other length for the shaft) - 01 pc.
R-8 (the red rims used for coupling) - 02 pcs.
Motor - 1 pc.MOTOR
A spanner and a screw driver for tightening the screws

Step 2: Assemble It All!

Though the pics make it more or less clear, go on to:

Mount the motor over the base you've selected (tightly bolt it in place! or screws might unscrew due to the vibrations produced!)
Couple the extending shaft with motor's shaft. (ignore this if your motor's shaft is already amply long).
Power it up! and see, if everythings working as it should..

Mechanix users: Please refer the pics--they're in the exact order in which I assembled the whole thing!

To make the LED holder, I used Sugru!
I placed a small amount of sugru on one end of the shaft, then pierced it with the LEDs, exactly the way I wanted the LEDs to be... then just allowed sugru to set and done!!!

Now, just put an LED in its place, switch on the power and sand the LED....

Step 3: Tips & Safety/Warnings

Tips:

To compensate for vibrations (leading to rattling noise), add some weight to
- base as well as
- shaft
Instead of sugru (and rendering the shaft useless for other purposes) tape the led to the shaft!!! (though, this is feasible only if you plan to diffuse a few LEDs..)
Use a fine sand paper (the one with grit=200 works good).

Warnings/Safety:

Use sand paper cautiously--it may hurt!
Don't use motor too long on extra power--it may get burned!
Always wear an eye protection of some sort!

Step 4: Other Relevant Info

I've used this thing for diffusing 45 LEDs and it worked pretty well.. Also, I didn't buy a single thing... just found everything lying around.. so, the cost involved was zero for me..

In case you were previously hand sanding the LEDs, and didn't use any specialised tool, this one will surely make the job much easier and it's pretty simple and fast to assemble it and then disassemble it when done!
Also, if batteries are used to power it, it becomes portable too!

Thanks For Taking Out Time To Read This Instructable!... :D

Reviews And Suggestions In Form Of Comments Are Welcomed!!!.... :D

And please ask if you have any questions! :)