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Roller chain ANSI B29.1 #25, #35, #40, #50, #60, #80: pitch, roller diameter, inner width, pin, plate height

What are the dimensions of ANSI #40 (or #25, #35, #50, #60, #80) roller chain: pitch, roller diameter, inner width, pin diameter, plate thickness and plate height? · Standard part · 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

Also called: #40 roller chain dimensions, #50 roller chain dimensions, #60 chain, #80 chain, #35 chain dimensions, #25 chain dimensions, ansi 40 chain pitch, ansi 50 chain pitch, roller chain size chart, chain roller diameter, roller chain inner width, roller chain plate height, asme b29.1 chain, 40 chain pin diameter, 40 chain pitch 1/2 in, roller chain pitch chart, ansi roller chain 80 pitch 1 inch

Exact dimensions. Every file is drawn at true size with no tolerance added. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your process's clearance before making the part. Mating features

sizes: 6 in table

Notes

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).

Roller chain ANSI B29.1 #25, #35, #40, #50, #60, #80: pitch, roller… size chart

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

Mating features

Drawn at the exact size. Open press, slide, run and socket features by your process's clearance (tolerances by process); leave designed gaps and clamp fits as drawn.

feature	exact	mates with	fit	files
inner width / roller Ø	W and Dr per chain no. (#40: 0.312 / 0.312 in)	sprocket tooth width 0.93 W − 0.006 and seat Ø 1.005 Dr + 0.003 (roller-chain-sprocket-dimensions-ansi, roller-chain-sprockets)	run	all

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

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
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
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
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
ASME	ASME B29.1-2011 Precision power transmission roller chains, attachments, and sprockets (the standard itself, paid)	web	Publisher's page; dimensions are facts
Tsubaki (US)	Roller chain, sprockets and TAPER-LOCK bushings: maker catalogue with CAD downloads	web	Publisher's page; dimensions are facts
Martin Sprocket	Martin Sprocket & Gear CAD library (sprockets, QD and taper bushings)	web	Publisher's page; dimensions are facts

Xem scan

File coming

No downloadable true-size file yet: the published figures do not fix the whole shape, and Xem never guesses a number. A measured scan is planned; request it and it moves up.

Let your AI pull this. Add https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.

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Plain text: sheet.txt · JSON: /api/geometry?object=roller-chain-ansi-b29-1-25-to-80

Schematic, not to scale.