Educational - mechanically deficient

The concept of the balance scale has convinced me as a teacher with 35 years of professional experience. For our grandson of three years it seemed to be a meaningful toy.
After unpacking, I realized that the balance could not be balanced. This was caused by a lack of connection wire between the foot of a scale and two very thin metal sheets connecting the feet of both scales under the sheet metal. The wire was missing Duch a small safety pin replaced, which could not heruausfallen again.
Unfortunately I had to find one of the two tiny dasss tapping screws that should hold the bottom plate, then no longer gripped. So I replaced it with a slightly larger.
As the birthday girl wanted curious to try the scales out of the box, the same error occurred again. So again, the bottom plate is removed and found that the second wire was now also slipped. As before repair!
For a price of nearly 37, - the quality is very poor. What lies at mechanics under the base plate, is just botch! Cheap material and apparently delivered without quality control.
Conclusion: Good thinking but badly done!