American standards for fasteners
Thread Content
I need to use fasteners that meet American standards, but I don’t have any relevant information available. Could anyone with expertise please help me? Thank you
In American standards, threads are generally designated in this way: 0.25–20UNF–2A; previously it was denoted as 1/4–20UNF–2A. ①②③④: ① – Nominal diameter (currently expressed as a decimal value representing the major diameter, with the unit being inches); ② – Number of threads per inch (i.e., pitch); ③ – Thread series code; ④ – Thread grade code. Note: For thread series with a nominal diameter smaller than 1/4 inch, the value indicated in ① is not the actual inch value of the nominal diameter, but rather a code represented by the numbers 0, 1, 2, 3, 4, 5, 6, 8, 10, and 12. The major diameter (in) of the threads with codes 0, 1, 2, 3, 4, 5, 6, 8, 10, 12 are respectively: 0.060, 0.073, 0.086, 0.099, 0.112, 0.125, 0.138, 0.164, 0.190, 0.216 ； The number of threads per inch for coarse thread types are: —, 64, 56, 48, 40, 40, 32, 32, 24, 24 ； The number of threads per inch for fine-thread screws are: 80, 72, 64, 56, 48, 44, 40, 36, 32, 28. For detailed information, try looking it up on Standard Sharing website. If you can’t find it, then I guess you’ll have to buy it:L
Search online for HG20631 as a US standard for fasteners