Essential Mechanisms: Mesh Gear.

Turn the handle on the side of the box and the interlocking gear teeth drive the vertical shaft. Make the model as a demonstration of pure mechanism or use it as a starting point for your own character based automata.

Members can download the project for free at the link. Thanks for signing up! Non members can download the parts for £2.50. Once you have downloaded the file, print out the pieces onto thin card. (230 gsm / 67lb) I used coloured card for a colourful model. You can use coloured, white or patterned card. The choice is yours.

Score along the dotted and dashed lines and cut out the holes before carefully cutting out the pieces.

Start by making the two gears. They are made from double thickness card. Fold over the pieces and glue them together. Once the glue is dry carefully cut out the teeth.

Make up the crank in three steps.

Fit the nine tooth gear to the crank handle. Line it up with grey line on the handle shaft.

Roll up the two axle tubes and glue down the edges so that they are lined up with the arrow points as shown.

Glue the an axle tube into the handle pushing it completely home.

Glue the short axle tube into the gear, again lining it up with the grey line.

Thread the axle tube into place so that the short axle tube is between the two grey lines.

Fold up the box inner as shown. The end tabs are folded round and glued down to make equilateral triangle tubes. Note that dashed lines are hill folds, dotted lines are valley folds.

Assemble the two short stiffeners and glue them into place on the underside of the box inner as shown. They should be roughly two millimetres from the hole.

Assemble the two box sides. The side tubes are right angled triangles and the end tube is an equilateral triangle.

Fold up and glue down the triangle tube sections on the box top.

Assemble the two box top stiffeners and glue them to the underside of the box. They should be a couple of millimetres from the hole in the box top.

Glue the two box sides to the folded up box inner as shown.

Fold up the box sides and glue them to the box inner as shown. Keep the box centre as square as possible.

Thread the small gear shaft through one side hole in the box inner, through the alignment piece, and out the other side.

Drop the larger gear into place so that it meshes with the other gear.

Complete the mechanism by gluing the box top into place.

As the handle is turned the gears mesh and the vertical shaft is rotated.

The rotation of the vertical shaft can be difficult to see. The hand makes it clearer.

Glue the two halves of the hand together leaving the middle unglued. Slip the completed hand over the vertical shaft.