You get a whole lot of it comes, and also has its reason. Not only do they break very quickly if one uses too much pressure or shearing forces (which can happen when screwing), they wear out very quickly. To cut a 1.5 mm thick and 30 cm long aluminum plate by, I had to use 6 or 7 discs, as these ruckzuck became smaller. In plastic and other soft materials they hold very long.
