Trapezoidal lead screw threads Tr10 to Tr40 (ISO 2904 / DIN 103): Tr10x2, Tr12x3, Tr16x4, Tr20x4, Tr24x5, Tr30x6, Tr40x7: pitch, d2, D4, d3, D1 — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/trapezoidal-threads-tr10-tr40-iso-2904/ (sheet CC BY 4.0) Basis: ISO 2904:2020 sample table (iTeh) with formula checks on every row; fasten.it, Roymech and AmesWeb as comparison; numbers only Catalog version: 2026-10-20 Sizes: see table below - Tr is the metric trapezoidal (30 degree flank angle) lead-screw thread: Tr10x2 means 10 mm nominal diameter and 2 mm pitch. For a single-start screw the lead equals the pitch; a multi-start thread has lead = P x starts and is written Tr d x lead (P pitch). The standard's formulas: D1 = d - P, d2 = D2 = d - 0.5 P, D4 = d + 2 ac, d3 = d - P - 2 ac (ac is the crest clearance, which differs by pitch). - Numbers: the ISO 2904:2020 sample (iTeh) table for Tr10 to Tr40 (44 d x P combinations); the generator re-checks D1 = d - P, d2 = d - 0.5 P and d3 = d - P - 2 ac on every row (ac = (D4 - d) / 2). AmesWeb's limits tables print the same screw minor and nut major values where compared (Tr10x1.5: d3 8.200, D4 10.300; Tr16x4: d3 11.500; Tr40x7: d3 32.000). - Disagreements kept: fasten.it's copy of the table (a cancelled-DIN reproduction) prints Tr10x1.5 with D4 11, d3 8 and D1 7.5, Roymech with D4 11, d3 2.000 and D1 3.000; the ISO 2904 sample and AmesWeb both give D4 10.3, d3 8.2, D1 8.5, which the formulas confirm. fasten.it, Roymech and AmesWeb also list Tr16x3 (and Tr18x3, Tr20x3 on AmesWeb), which the ISO 2904 sample table does not; Tr16x4 is in the ISO sample (and AmesWeb) but fasten.it and Roymech print Tr16x3 in its place. Those rows are not used here. - Numbers only, no files: a lead screw's length, ends and start count are chosen by the user, and the helical thread is not a published envelope. For modelled lead screws see the T8 lead screw and the Tr10x2 screw pages. - Left out: the external / internal tolerance classes (7e, 7H and so on), the multi-start leads, Tr sizes above 40 mm, ac / H4 / h3 values per pitch (not in the sample). thread nominal Ø d, mm pitch P, mm pitch Ø d2 = D2, mm nut major Ø D4, mm screw minor Ø d3, mm nut minor Ø D1, mm Tr10x1.5 10 1.5 9.250 10.300 8.200 8.500 Tr10x2 10 2 9.000 10.500 7.500 8.000 Tr11x2 11 2 10.000 11.500 8.500 9.000 Tr11x3 11 3 9.500 11.500 7.500 8.000 Tr12x2 12 2 11.000 12.500 9.500 10.000 Tr12x3 12 3 10.500 12.500 8.500 9.000 Tr14x2 14 2 13.000 14.500 11.500 12.000 Tr14x3 14 3 12.500 14.500 10.500 11.000 Tr16x2 16 2 15.000 16.500 13.500 14.000 Tr16x4 16 4 14.000 16.500 11.500 12.000 Tr18x2 18 2 17.000 18.500 15.500 16.000 Tr18x4 18 4 16.000 18.500 13.500 14.000 Tr20x2 20 2 19.000 20.500 17.500 18.000 Tr20x4 20 4 18.000 20.500 15.500 16.000 Tr22x3 22 3 20.500 22.500 18.500 19.000 Tr22x5 22 5 19.500 22.500 16.500 17.000 Tr22x8 22 8 18.000 23.000 13.000 14.000 Tr24x3 24 3 22.500 24.500 20.500 21.000 Tr24x5 24 5 21.500 24.500 18.500 19.000 Tr24x8 24 8 20.000 25.000 15.000 16.000 Tr26x3 26 3 24.500 26.500 22.500 23.000 Tr26x5 26 5 23.500 26.500 20.500 21.000 Tr26x8 26 8 22.000 27.000 17.000 18.000 Tr28x3 28 3 26.500 28.500 24.500 25.000 Tr28x5 28 5 25.500 28.500 22.500 23.000 Tr28x8 28 8 24.000 29.000 19.000 20.000 Tr30x3 30 3 28.500 30.500 26.500 27.000 Tr30x6 30 6 27.000 31.000 23.000 24.000 Tr30x10 30 10 25.000 31.000 19.000 20.000 Tr32x3 32 3 30.500 32.500 28.500 29.000 Tr32x6 32 6 29.000 33.000 25.000 26.000 Tr32x10 32 10 27.000 33.000 21.000 22.000 Tr34x3 34 3 32.500 34.500 30.500 31.000 Tr34x6 34 6 31.000 35.000 27.000 28.000 Tr34x10 34 10 29.000 35.000 23.000 24.000 Tr36x3 36 3 34.500 36.500 32.500 33.000 Tr36x6 36 6 33.000 37.000 29.000 30.000 Tr36x10 36 10 31.000 37.000 25.000 26.000 Tr38x3 38 3 36.500 38.500 34.500 35.000 Tr38x7 38 7 34.500 39.000 30.000 31.000 Tr38x10 38 10 33.000 39.000 27.000 28.000 Tr40x3 40 3 38.500 40.500 36.500 37.000 Tr40x7 40 7 36.500 41.000 32.000 33.000 Tr40x10 40 10 35.000 41.000 29.000 30.000 Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - iTeh Standards: ISO 2904:2020 sample: ISO metric trapezoidal screw threads, basic dimensions, formulas and the d, P, d2, D4, d3, D1 table (Tr10 to Tr40) — web — Publisher's page; dimensions are facts — https://cdn.standards.iteh.ai/samples/78729/7d158726108b478c889fa887d460ba78/ISO-2904-2020.pdf - fasten.it: ISO 2904 (cancelled DIN 103 successor) trapezoidal thread table, reproduced by permission of DIN — web — Publisher's page; dimensions are facts — https://fasten.it/en/Norms/Norm/ISO%202904 - Roymech: Trapezoidal threads: metric table d, P, d2, D4, d3, D1 — web — Publisher's page; dimensions are facts — https://roymech.org/Useful_Tables/Screws/Trapezoidal.html - AmesWeb: Trapezoidal thread chart: external / internal major, pitch, minor diameter limits — web — Publisher's page; dimensions are facts — https://amesweb.info/Screws/trapezoidal-thread-chart.aspx 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=trapezoidal-threads-tr10-tr40-iso-2904