Hi, this toy chainsaw can be used on several occasions since trash movie to a fantasy party. It operates very simple: a button is pushed on the handle where it is held, which connects the engine and causes current to run. It was made with recycled materials that I had at home.
I hope you enjoy.

Step 1: Materials Needed

- 04 gears of a bicycle rear derailleur gears (screw, inner cylinder and the two caps, each);

- More than 02 screws to the inner cylinder;

- About 75cm bike chain (run);

- Slatted wooden box *

* I used 3mm balsa wood as he had at home. Can also be used thick cardboard (0.5 mm) which is much easier to find.

- Cart with a gear wheel, as figure;

or

- Standard servo modified for continuous rotation (see the internet how to make this change);

- 2 hangers (servo arm as shown);

- 2 small screws or glue to attach the hangers.

- 1 support for four batteries

- 1 normally open switch

- Hot glue, glue, ruler, pen, pencil, etc ...

Step 2: Preparing the Servo

After turning the servo to continuous rotation, solder two wires directly contacts the engine, by-passing the electronic circuit. I used the wire itself the servo, taking care to leave a tip of three wires which were originally linked to later be able to use again as a servo. That done, simply reassemble the servo. A good tutorial on how to put the servo continuous rotation:
http:// http://arduinianos.blogspot.com/

Combine the two crosses as figure using screws or gluing tight.

The crosses were selected because they have a center that fits mayor, allowing an optimal alignment between the servant and gear.

Step 3: Mounting Saw

The saw was made with a piece of old bike chain (about 75 cm) but would be very heavy. At first I put the chain on top of the strip and tried to find the best position for the gears. After that, I made the holes with a drill, mounted and fixed gears. I put the chain and marked with a pen so that when she was stretched, it should come as much as possible around the body of the strip. After these adjustments, I made a template to facilitate.

I made a servant to put the amount and stuck it into the body of the mountain by the same method of trial and error. It was found that the chain was still a little loose. Hence, I used two screws to the metal cylinder to stretch the chain a little. the result was very good.

Note: This metal cylinder must be supported only by the screw, that is, it must run to pass the stream.

Step 4: Body of the Saw

The body of the saw was made of cardboard.

materials:

- Cardboard

* Note: I used a 0.5 cm thick. This determined the distance between the edge of the body and the workpiece support.

- Hot glue;

Print layout and paste the picture on the cardboard . Cut and assemble.

Now, just paint and is ready