Chip formation: The process by which material is removed from a workpiece during cutting, resulting in the creation of chips that are ejected from the machining zone.

NPT threadangle

Abrasion: The process of wearing away a material through friction or contact with harder surfaces, often contributing to cutting wear.

Cutting wear is the process by which material is removed from a surface through the action of sharp edges, typically seen in machining and grinding processes. This type of wear is characterized by the deformation and removal of material as tools or abrasives slide across the workpiece, resulting in a loss of material integrity and surface finish. Understanding cutting wear is essential for optimizing tool life and performance in manufacturing applications.

L2 = Effective length of thread = Truncation from point of thread triangle to flat (not shown in diagram). Minimum = 0.033P for all pitches. See table for maximum.

Npt threadsizes

Tool wear: The gradual deterioration of a cutting tool due to friction, heat, and mechanical stress during machining operations.

Note: Basic dimensions are given to four or five decimal places to eliminate errors when calculating gauge dimensions, they do not imply a greater degree of precisions than is normally obtainable. Metric dimensions, where shown, are calculated from the inch values and rounded.

Npt threadchart

Tolerances When using L1 gauges to check threads, the thread is within permissible tolerance if the ring gauge face, or plug gauge notch, is +/- 1 turn from being flush with the end of the thread.

L1 = Length of normal hand-tight engagement. This is also the L1 gauge length. (Longer thread engagement may be used in special applications, such as flanges for high pressure use. In such cases the pitch diameter, E, remains as specified and the diameter at the end of the pipe is proportionally smaller.)