Acme threads 1/4-16 to 2-4 (ASME B1.5): 1/2-10, 5/8-8, 3/4-6, 1-5, 1-1/2-4, 2-4: major, pitch and minor diameter, pitch — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/acme-threads-asme-b1-5-1-4-to-2-in/ (sheet CC BY 4.0) Basis: Bornemann Gewindetechnik ASME B1.5 nominal-dimension table with formula checks on every row and MachiningDoctor pages for 5/16-14 and 2-4; numbers only Catalog version: 2026-10-20 Sizes: see table below - General-purpose Acme (ASME B1.5, 29 degree flank angle) is the inch lead-screw thread: 1/2-10 Acme is a 1/2 in screw with 10 threads per inch, so the pitch (and, single-start, the lead) is 0.100 in. The basic formulas are d2 = d - P/2 and d1 = d - P; the generator checks both, and P = 1/TPI, on every row. - Numbers: Bornemann Gewindetechnik's ASME B1.5 nominal-dimension table (inches as printed), with MachiningDoctor's 5/16-14 and 2-4 pages as the independent check (5/16-14: major 0.3125, pitch 0.2768, minor 0.2411, pitch 0.07143; 2-4: pitch diameter 1.875, minor 1.75, pitch 0.25). The mm columns are the printed inch values times 25.4 (rounded to 0.01 mm). Bornemann's table runs on to 5-2 Acme; only 1/4 to 2 in are shown here. - Numbers only, no files: lead, start count and length are the user's choices and the helical form is not a published envelope. The Class 2G / 3G / 4G tolerance bands (MachiningDoctor prints them, e.g. 2-4 external pitch diameter 1.8402 to 1.8637 in) are left out. - Left out: stub Acme, centralizing Acme, Class 2G / 3G / 4G limits, multi-start leads, sizes above 2 in, the metric Tr thread (separate page). thread TPI major Ø d, in pitch P, in pitch Ø d2, in minor Ø d1, in d, mm P, mm d2, mm d1, mm 1/4-16 Acme 16 0.2500 0.0625 0.2188 0.1875 6.35 1.59 5.56 4.76 5/16-14 Acme 14 0.3125 0.0714 0.2768 0.2411 7.94 1.81 7.03 6.12 3/8-12 Acme 12 0.3750 0.0833 0.3333 0.2917 9.53 2.12 8.47 7.41 7/16-12 Acme 12 0.4375 0.0833 0.3958 0.3542 11.11 2.12 10.05 9.00 1/2-10 Acme 10 0.5000 0.1000 0.4500 0.4000 12.70 2.54 11.43 10.16 5/8-8 Acme 8 0.6250 0.1250 0.5625 0.5000 15.88 3.18 14.29 12.70 3/4-6 Acme 6 0.7500 0.1667 0.6667 0.5833 19.05 4.23 16.93 14.82 7/8-6 Acme 6 0.8750 0.1667 0.7917 0.7083 22.23 4.23 20.11 17.99 1-5 Acme 5 1.0000 0.2000 0.9000 0.8000 25.40 5.08 22.86 20.32 1-1/8-5 Acme 5 1.1250 0.2000 1.0250 0.9250 28.58 5.08 26.04 23.50 1-1/4-5 Acme 5 1.2500 0.2000 1.1500 1.0500 31.75 5.08 29.21 26.67 1-3/8-4 Acme 4 1.3750 0.2500 1.2500 1.1250 34.93 6.35 31.75 28.58 1-1/2-4 Acme 4 1.5000 0.2500 1.3750 1.2500 38.10 6.35 34.93 31.75 1-3/4-4 Acme 4 1.7500 0.2500 1.6250 1.5000 44.45 6.35 41.28 38.10 2-4 Acme 4 2.0000 0.2500 1.8750 1.7500 50.80 6.35 47.63 44.45 Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - Bornemann Gewindetechnik: ACME thread according to ANSI / ASME B1.5-1977, nominal dimensions: d, d2 = D2, P, d1, 1/4-16 to 5-2 (with 3D model links) — web — Publisher's page; dimensions are facts — https://www.bornemann-gewindetechnik.de/en/products/acme-screws-and-leadscrews/data/ - MachiningDoctor: Acme thread basic dimensions (ASME B1.5): 5/16-14 and 2-4 pages (TPI, pitch, major, pitch, minor diameter) — web — Publisher's page; dimensions are facts — https://www.machiningdoctor.com/threadinfo-acme/?tid=5001 No true-size file yet: the published figures do not fix the whole shape; a measured scan is planned. API: https://xemstudio.com/api/geometry?object=acme-threads-asme-b1-5-1-4-to-2-in