Long Series - 2 Flute - Metric For optimum performance and maximum swarf removal when plunging, slotting and routing in light alloys, brass, aluminium, non ferrous and other soft materials. Manufactured to USCTi Standards. Metric Tolerances Diameter: Over 1.00 ~ up to 6.00. Tolerance: +0.000, -0.050. Diameter: Over 6.00 ~ up to 25.00. Tolerance: +0.000, -0.080.