Showing posts with label Threads and Threading. Show all posts
Showing posts with label Threads and Threading. Show all posts

American Pipe Threads

American National Standard pipe threads described in the following paragraphs provide taper and straight pipe threads for use in various combinations and with certain modifications to meet these specific needs.

Thread Designation and Notation.—American National Standard Pipe Threads are designated by specifying in sequence the nominal size, number of threads per inch, and the symbols for the thread series and form, as: 3⁄8—18 NPT. The symbol designations are as follows: NPT—American National Standard Taper Pipe Thread; NPTR—American National Standard Taper Pipe Thread for Railing Joints; NPSC—American National Standard Straight Pipe Thread for Couplings; NPSM—American National Standard Straight Pipe Thread for Free-fitting Mechanical Joints; NPSL—American National Standard Straight Pipe Thread for Loose-fitting Mechanical Joints with Locknuts; and NPSH— American National Standard Straight Pipe Thread for Hose Couplings.

American National Standard Taper Pipe Threads.—The basic dimensions of the ANSI Standard taper pipe thread are given in Table 1a.

Metric Threaded Fasteners


List of Standard ANSI for Metric Screws:

Table 1 ANSI B18.2.3.1M-1979 (R1989) Metric Hex Cap Screws
Table 2 ANSI B18.2.3.2M-1979 (R1989) Metric Formed Hex Screws
Table 3 ANSI B18.2.3.3M-1979 (R1989) Metric Heavy Hex Screws
Table 5 ANSI B18.2.3.8M-1981 (R1991) Metric Hex Lag Screws
Table 6 ANSI B18.2.3.9M-1984 Metric Heavy Hex Flange Screws
Table 7 ANSI B18.2.3.4M-1984 Metric Hex Flange Screws
Table 9 ANSI B18.5.2.2M-1982 Metric Round Head Square Neck Bolts
Table 10 ANSI B18.2.3.6M-1979 (R1989) Metric Heavy Hex Bolts
Table 11 ANSI B18.2.3.7M-1979 (R1989) Metric Heavy Hex Structural Bolts
Table 12 ANSI B18.2.3.5M-1979 (R1989) Metric Hex Bolts

Unified Screw Threads

American Standard for Unified Screw Threads

American Standard B1.1-1949 was the first American standard to cover those Unified
Thread Series agreed upon by the United Kingdom, Canada, and the United States to
obtain screw thread interchangeability among these three nations. These Unified threads
are now the basic American standard for fastening types of screw threads. In relation to
previous American practice, Unified threads have substantially the same thread form and
are mechanically interchangeable with the former American National threads of the same
diameter and pitch.