31-21 – 3/8-16UNC 4131-3C1 4131-3C1B 13/16-16UN 4131-13D516 – No. 3-56UNF 4131-32 – 3/8-24UNF 4131-3C2 4131-3C2B 13/16-20UNEF 4131-13D3 – No. 4-40UNC 4131-41 4131-41B 3/8-32UNEF 4131-3C3 – 7/8-9UNC 4131-7C1 4131-7C1B No. 4-48UNF 4131-42 4131-42B 7/16-14UNC 4131-7D1 4131-7D1B 7/8-14UNF 4131-7C2 – No. 5-40UNC 4131-51 4131-51B 7/16-20UNF 4131-7D2 4131-7D2B 1-8UNC 4131-2A1 – No. 6-32UNC 4131-61 4131-6
