Because the belts and grinding wheels were wearing out quickly and breaking prematurely, they required frequent replacement. As a result, production lines shutdown for up to an hour at a time: the change-out time for grinding wheels was even longer.
On several occasions, the then current supplier could not deliver replacement belts on time, which shut the production line down for several days while the belt manufacturer made more belts. The immense downtime dramatically increased product-related cost, and hurt productivity.