Weighing Scale Plans

Materials You Will Need:

A block of wood 100 mm long x 20 mm x 20 mm for the support head.
A wooden dowel 300 to 500 mm long x 8 mm diameter for the horizontal dowel.
A wooden dowel 350 to 500 mm long x 10 mm diameter for the vertical dowel.
A block of wood 200 mm long x 100 mm wide by 30 mm thick for the base.
5mm and 10mm drill bits.
An electric or hand drill.
Wood glue.
Two cardboard seals from coffee bottles or similar to make the weighing pans.
Thin string.
Scissors.

Parts of the scale

Instructions:

To make the head, measure 10mm from one end of the block and drill a 5mm right through for the support string. Then measure in 15mm from the other end and drill a 10mm diameter hole 15mm deep. Put a little wood glue on the end of the vertical dowel and glue it into this hole.
To make the base, measure to the centre of the base block and drill a 10mm diameter hole 25mm deep. Glue the other end of the vertical dowel into this making sure the head faces to the front.
To make the horizontal dowel, tie a short length of string through the 5mm hole in the head and to the middle of the horizontal dowel so that it hangs about 50mm below the head. This should be just tight enough so that you can slide it along the horizontal dowel rod and be able to balance the balloons.
Tie on equal lengths of string to each end of the horizontal dowel (or three strings per side if you want to add weighing pans).
To make weighing pans, punch three evenly space holes (5mm in) around the circumference of a coffee bottle cardboard seal (or small aluminium pie dish). Tie the three strings to the holes and ensure that both pans lie level and are of the same length.
Move the centre string until the dowel balances and you are ready to weigh!