The main difference is that the thread profile is tapered at an angle of 1☄7′ (0.75 in/ft or 62.5 mm/m) relative to the axis. The basic profile is a 60° truncated triangle similar to the Unified Inch threads (UNC/UNF). An endmill holder may be used with caution, but might require modifications to speed and feed recommendations, to avoid chatter and excessive tool deflection.NPT stands for National Pipe Tapered threads. We recommend using a hydraulic chuck, milling chuck, or shrink-fit toolholder. Typically, a collet chuck does not provide the necessary rigidity to cut high-quality threads. Thread mills cut with the side of the tool, so it is very important to use the most rigid toolholders. For external left-hand threads, program the helical interpolation direction with clockwise arcs (G02), with the Z-axis starting at the deepest point, and feeding up (Z positive) by the amount of the pitch of the thread. For internal left-hand threads, program the helical interpolation direction with counterclockwise arcs (G03), with the Z-axis starting above the deepest point, and feeding down (Z negative) by the amount of the pitch of the thread.įor external right-hand threads, program the helical interpolation direction with clockwise arcs (G02), with the Z-axis starting above the deepest point, and feeding down (Z negative) by the amount of the pitch of the thread. For internal right-hand threads, program the helical interpolation direction with counterclockwise arcs (G03), with the Z-axis starting at the deepest point, and feeding up (Z positive) by the amount of the pitch of the thread. Climb milling generates less heat and less tool deflection, which leads to vibration.Īlways program the spindle in the forward direction (M03). Always program climb milling for better surface finish and improved tool life.

Thread milling npt mastercam