ASME B1.20.1:2013 pdf free download

ASME B1.20.1:2013 pdf free download.Pipe Threads,General Purpose(Inch).
This formula determines the length of effective external thread. This may include two usable threads incomplete at the crest.
3.1.8 Hand-Tight Engagement Between External and Internal Taper Threads. The basic length of engagement between external and internal taper threads when screwed together hand-tight is L1, shown in column 6, Table 2.
3.1.9 Wrench-Tight Engagement Between External and Internal Taper Threads. The external thread length, L2 — L1, and the internal thread length, L3, are allowances for wrench-tight assembly after the hand-tight engagement of L1 lengths.
3.1.9.1 Thread Engagement Considerations. The gaging tolerance of ±1 turn for both external and internal threads has the effect of potentially increasing the length of engagement by up to two turns or reducing the length of engagement by up to two turns. Working gage wear has the additional effect of reducing thread engagement by the amount gages wear past basic.
3.1.9.2 Special Applications. It is recognized that in special applications, such as flanges for high-pressure work, longer thread engagement is needed, in which case the pitch diameter (dimension E1, Table 2) is maintained and the pitch diameter E0 at the end of the pipe is made smaller. The taper must be kept at 3’. in./ft, and thread is made longer.
3.1.10 Tolerances on Product Taper, Lead, and Angle. The permissible variations in taper. lead, and angle are given in Table 3. This table is a guide for establishing limits of the thread elements of threading tools. The correct manufacture of tools and the use of gages should provide adequate control of functional size.
3.1.11 Basic Dimensions. The basic dimensions of taper pipe threads, derived from the above specifications, are given in Table 2.
3.2 Gaging NPT Threads
The L1 gages prescribed in this Standard are considered functional in that they give assurance of assemblability over the L1 length, the length of hand-tight engagement. They simulate a mating product thread that conforms to this Standard. They encompass multiple elements of the thread, including thread diameters, flank angle, lead, taper, and root truncation. The simultaneous engagement of all elements results in a measurement that reflects the cumulative variation of all those elements, the functional diameter. This is expressed as standoff for rings and plugs or measured directly by indicating gages. See section 7 for gage specifications.
3.2.1 External Thread Gaging
3.2.1.1 L1 Ring Gage.