Carmex Thread Mills Solid Carbide - Internal Thread - Metric - M3, M4 x 0.5 - MT7Carmex MT line Thread Mills deliver precise, cost efficient internal threading for metric sizes on CNC machines. Designed for engineers and machinists who need reliable M3 and M4 x 0. 5 threads without extra tapping steps. Solid Carbide Construction: High rigidity and wear resistance for consistent thread quality and long tool life. Internal Thread Milling: Create clean, finished threads from within the workpiece, reducing the need for taps. Metric