Roller chain ANSI B29.1 #25, #35, #40, #50, #60, #80: pitch, roller diameter, inner width, pin, plate height — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/roller-chain-ansi-b29-1-25-to-80/ (sheet CC BY 4.0) Basis: ASME B29.1M roller chain table as published by Engineers Edge, cross-checked against Martin Sprocket, A-Metric and Peer Chain; disagreements are shown; maker CAD linked Catalog version: 2026-10-20 Sizes: see table below - ANSI (ASME B29.1) roller chain numbers follow the pitch in this table: the digits before the final 0 are the pitch in eighths of an inch (#40 = 4/8 = 1/2 in, #50 = 5/8, #60 = 6/8 = 3/4 in, #80 = 8/8 = 1 in; #25 = 2/8 and #35 = 3/8 in). Engineers Edge marks #25 and #35 as bushing chain without rollers: their 'roller' Ø in the table is the bushing Ø. - Agreement: pitch, roller Ø, inner width, pin Ø and plate thickness for all six sizes come from Engineers Edge's ASME B29.1M table. Martin Sprocket prints the same roller width and roller Ø for all six; A-Metric agrees to rounding (roller Ø within 0.002 in, pin Ø within 0.001 in, plate thickness within 0.0035 in, #40's 0.313 vs 0.312). Roller Ø and inner width are maxima / nominal catalogue values; the standard's tolerances are not tabulated here. - Disagreements, shown rather than averaged: plate height. Engineers Edge gives the standard's maximum roller-link plate height as 0.95 P (0.238, 0.356, 0.475, 0.594, 0.713, 0.950 in; pin-link plates are lower at 0.82 P); A-Metric prints the plate depth h2 slightly lower (0.236, 0.354, 0.472, 0.594, 0.709, 0.945) and Peer Chain prints 0.228 for #25 and 0.712 for #60. Plate height is a maximum, so 0.95 P is the limit to design a guard or a housing around; real plates vary by maker. A-Metric's inside widths (0.309, 0.370, 0.495, 0.620 for #40, 50, 60, 80) are slightly under the 0.312 / 0.375 / 0.500 / 0.625 of the other tables. - Peer Chain's size chart disagrees in two places and is not used for those values: #80 pitch printed as 1.25 in (the other four sources, and the chain number itself, say 1.000 in) and #50 roller Ø / width printed as 0.375 / 0.400 (Engineers Edge, Martin and A-Metric: roller Ø 0.400, width 0.375, so those two columns look swapped there). Its #60 pitch prints 0.751. - Widths: 'roller link width max' is Engineers Edge's W + 2.12 × plate thickness (the outer width of an inner link). 'Overall width' is A-Metric's chain width over pin ends; connecting links are wider. Measuring load is the chain length-measuring load in ASME B29.1M as printed by Engineers Edge (lbf). - No files: the link plate is a peanut shape whose waist depth and end radii are in the standard's drawing, not in the tables read, so a chain model would be invented. Sprocket dimensions for these chains are on the companion page; the existing roller-chain-sprockets page has simplified #25 and #35 sprocket files. - Chain CAD: Tsubaki and Martin publish CAD for their own chain and sprockets (linked below); the standard itself is ASME B29.1-2011 (paid). ANSI chain no. pitch P, in (mm) roller Ø Dr max, in (mm) inner width W, in (mm) pin Ø, in (mm) plate thickness, in (mm) plate height max (0.95 P), in (mm) plate height, A-Metric h2, in plate height, Peer H, in roller link width max, in (mm) overall width, A-Metric, in measuring load, lbf #25 0.250 (6.35) 0.130 (3.30) 0.125 (3.17) 0.0905 (2.30) 0.030 (0.76) 0.238 (6.05) 0.236 0.228 0.189 (4.80) 0.311 18 #35 0.375 (9.52) 0.200 (5.08) 0.188 (4.78) 0.1410 (3.58) 0.050 (1.27) 0.356 (9.04) 0.354 0.356 0.294 (7.47) 0.488 18 #40 0.500 (12.70) 0.312 (7.92) 0.312 (7.92) 0.1560 (3.96) 0.060 (1.52) 0.475 (12.06) 0.472 0.475 0.439 (11.15) 0.654 31 #50 0.625 (15.88) 0.400 (10.16) 0.375 (9.52) 0.2000 (5.08) 0.080 (2.03) 0.594 (15.09) 0.594 0.594 0.545 (13.84) 0.815 49 #60 0.750 (19.05) 0.469 (11.91) 0.500 (12.70) 0.2340 (5.94) 0.094 (2.39) 0.713 (18.11) 0.709 0.712 0.699 (17.75) 1.020 70 #80 1.000 (25.40) 0.625 (15.88) 0.625 (15.88) 0.3120 (7.92) 0.125 (3.17) 0.950 (24.13) 0.945 0.950 0.890 (22.61) 1.287 125 Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - Engineers Edge: Roller chain dimensions per ASME/ANSI B29.1M: pitch, max roller Ø, width, pin Ø, plate thickness, plate height formulas (0.95 P roller link, 0.82 P pin link) — web — Publisher's page; dimensions are facts — https://engineersedge.com/power_transmission/roller_chain_dimensions_13610.htm - Martin Sprocket: Sprocket engineering data: PD = pitch / sin(180 / N), OD = pitch (0.6 + cot(180 / N)), roller width and diameter, single-strand tooth width table — web — Publisher's page; dimensions are facts — https://www.martinsprocket.com/docs/catalogs/engineering/engineering%20catalog/sprocket-engineering-data.pdf - A-Metric: ANSI roller chain: pitch, roller Ø, inside width, pin Ø, plate thickness, plate depth h2, overall width — web — Publisher's page; dimensions are facts — https://www.ametric.com/images/document/Chain-RollerANSI.pdf - Peer Chain: Single strand roller chain size chart: pitch, roller Ø, width, pin Ø, plate thickness, plate height — web — Publisher's page; dimensions are facts — https://www.peerchain.com/wp-content/uploads/2024/09/Single-Strand-Roller-Chain-Size-Chart.pdf - ASME: ASME B29.1-2011 Precision power transmission roller chains, attachments, and sprockets (the standard itself, paid) — web — Publisher's page; dimensions are facts — https://webstore.ansi.org/standards/asme/asmeb292011r2022 - Tsubaki (US): Roller chain, sprockets and TAPER-LOCK bushings: maker catalogue with CAD downloads — web — Publisher's page; dimensions are facts — https://www.tsubaki.com/ - Martin Sprocket: Martin Sprocket & Gear CAD library (sprockets, QD and taper bushings) — web — Publisher's page; dimensions are facts — https://www.martinsprocket.com/ 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=roller-chain-ansi-b29-1-25-to-80