At fist lets's take a file-roll from a lighter and use it as a rotary riffler. It's easy to make, simple and old idea, but... it very useful bit, must have!

Second, sanding disks made from an abrasive paper. Many publications on this... But how to cut quickly and sharp? My method is based on preliminary making the hole-puncher and rotary blade.

Then the main draw - sanding sandpaper flap wheel disks. Examples of grinding, what surface finish look like when you use this wheels of different grits.

Step 1: Tutorial How to Make & Applications

Timing

0:03 - Needle-file from a lighter roll

1:22 - Hole-puncher for making even center holes of sanding discs

3:39 - Rotary blade bit making

4:19 - Sanding disks cutting

5:47 - Paper drum-basis making

7:34 - Sandpaper flap wheel disk making

8:43 - Examples of surfaces grinded with different grits

Some notes. The diameter of rubber drum - 12.9 mm, so I had to grind off slightly to lower it to 12.6 mm. To stick paper elements it was used joiner's glue Moment for wood.

Step 2: Output

So, we have made: rotary riffler, 2 auxiliary conveniences for cutting disks with accurate 1.8-2.0 mm center holes, flap wheel disc 40 grit (and off-camera 80 and 500 grit in the same maner).