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Make NPT in solidworks
2. Find out the outside diameter of pipe according to the table. Draw a cylinder with that diameter.
For example, for a NPT size of 1, the outside diameter of pipe is 1.315 inches = 33.4 mm.
crests located against the the vanish threads. The length, L1, is the normal engagement between external
and internal taper threads when screwed together hand tight. According to the table, for size 1, the effective thread length L2 should be 0.683 inches = 17.3482 mm and the vanish thread length V should be 0.302 inches = 7.6708 mm. Total length L4 = 0.985 inches = 25.02 mm.
Find out the Pitch Diameter At Beginning of External Thread E0. This is the revolving diameter of the midpoint of the triangle at the beginning of the thread. Select the midpoint of one edge of the triangle. Set the distance between this point and the centerline according to E0. For NPT size of 1, E0 = 1.2136 inches = 30.825 mm.
Sketch, convert the outline of the taper surface to sketch segment.
Create the helix. Constant pitch equals 2.209 mm, clockwise, taper helix 1.7899° outward.