Can you imagine if car wheels and tyres were manufactured without checking tolerances (measurements) ? The car below has wheels and tyres that should be exactly the same. However, they were manufactured without tolerance checks being made. As a result the wheels and tyres are slightly different sizes and the car is dangerous as a result.

The digital vernier caliper is a very accurate measuring device. It is being used to check that the steel bolt falls within 81mm and 80mm in length . If it is outside these measurements (tolerance) it will be rejected.

If the measurement falls between -0.5mm less than 80.50mm or +0.5mm above 80.50mm then the bolt is within tolerance and will not be rejected. Any measurement outside this range and the bolt is rejected.

1. Explain why tolerance is important when checking the quality / accuracy of a product.

2. If a product or component is rejected because it falls outside the set tolerance it is normally rejected. Instead of discarding or dumping the component how could its material be used again ?