Left: Outlines of the 5 components of the balance have to be drawn on a postcard:      1. Two pans     2. Two supporting bars (connecting the pans with 4)   3. Central pole
4. Two parallel bars   5. Base.
Right: The 5 components assembled.
 

1a Cut out the two pans,
     cut in at the 4 corners only once:
     upper left corner from upside, upper right from right,
     lower left corner from left, lower right from down.
1b Fold up the 4 sides along the dotted line.
1c Paste the margins at the 4 corners.

2. Cut out the postcard strips for the two supporting bars of the pans,
    fold them along the dotted lines, paste the margins,
    paste the supporting bars and the pans.

3. Cut out the central pole.
    Cut out the windows for the parallel bars, cut out the lower right corner and fold along
    the dotted lines. Paste b and b´ to obtain the central pole like seen in the middle photo.
5. Cut the base and paste it with the  4 c-parts (on the center).

4. Cut out the parallel bars, fold and paste them.
Assemble the scale: Use two needles to connect parallel bars and the central pole. Four more needles are needed to combine the supporting bars and the parallel bars.