Hello,
In this instructable you will see how to turn your old ventilator into a brand new belt sander.
Steps overview:
1. Disassembling the ventilator
2. Preparing the mounts
3. Preparing the belt
4. Turn it on and sand something

You will need:
Lots of good mood :)

Materials:
an old ventilator
Sand paper
10mmX1.5mm aluminum pipe (50 mm length)
Plastic rod - 30mm diameter, 50mm length (i used PVC, but it can be any kind of plastic)
Double sided duct tape tesa® 4900

Tools:
Dremel (Accessories - contour sander+ disc)
screwdriver
screwing machine
Hammer
Locking pliers
Socket set/wrench
M6 screw
2 M6 nuts
woodscrew
6.2 mm drill
10.0 mm drill

Step 1: Disassembling the Ventilator

1. Disassemble the front and back covers (using the screwdriver)
2. Disassemble the fan (using the socket)
3. Drill a hole in the exterior diameter and screw on the wood screw to the frame(to prevent the vertical rotation)
4. Drill a 6.2mm hole in the side of the casing (be sure not to drill on electric wires)
5. Open the screws in the area of the hole.
6. Insert the M6 screw into the hole from the inside and tighten the nut.

Step 2: Preparing the Mounts

1. Drill a 10mm hole in the middle of the plastic rod.
2. Insert the aluminum pipe into the hole using the hammer.
3. Insert the small mount onto the M6 screw you inserted in step 1.
4. Close the mount location using a nut (make sure not to tighten it too much in order to enable the mount to turn freely)
5. Remover the blades from the fan using the Dremel (use the disc accessory)
6. Polish the remaining plastic using the contour sander)
7. Insert the large mount onto the motor shaft and secure with the original nut.

Step 3: Preparing the Belt

1. Cut the belt to size (make sure to leave enough overlapping area).
2. Use the double sided duct tape to fix the size of the belt on the mounts (dont tighten too much, it will overload the motor)
3. Cut the sand paper into strips.
4. Use the double sided duct tape to tape the sandpaper on the belt.

Step 4: Turn It on and Sand Something

1. Turn on the ventilator (you can choose speed)
2. Sand something
3. Cool huh?

Note: The ability of this belt sander is limited, the ventilator motor is not as strong as we think, and therefore if we apply large pressure it will stop.