# 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?

- Category: Hardware › Bearings, rails & motion
- Kind: 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
- Page: https://xemstudio.com/objects/roller-chain-ansi-b29-1-25-to-80/ · JSON: https://xemstudio.com/api/geometry?object=roller-chain-ansi-b29-1-25-to-80 · Plain text: https://xemstudio.com/objects/roller-chain-ansi-b29-1-25-to-80/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
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**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.

## 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).

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp 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 |

## Sizes

| 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 |

## Where the files are

- 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)](https://engineersedge.com/power_transmission/roller_chain_dimensions_13610.htm) — 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](https://www.martinsprocket.com/docs/catalogs/engineering/engineering%20catalog/sprocket-engineering-data.pdf) — 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](https://www.ametric.com/images/document/Chain-RollerANSI.pdf) — 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](https://www.peerchain.com/wp-content/uploads/2024/09/Single-Strand-Roller-Chain-Size-Chart.pdf) — web — Publisher's page; dimensions are facts
- ASME: [ASME B29.1-2011 Precision power transmission roller chains, attachments, and sprockets (the standard itself, paid)](https://webstore.ansi.org/standards/asme/asmeb292011r2022) — web — Publisher's page; dimensions are facts
- Tsubaki (US): [Roller chain, sprockets and TAPER-LOCK bushings: maker catalogue with CAD downloads](https://www.tsubaki.com/) — web — Publisher's page; dimensions are facts
- Martin Sprocket: [Martin Sprocket & Gear CAD library (sprockets, QD and taper bushings)](https://www.martinsprocket.com/) — web — Publisher's page; dimensions are facts

## Questions

**What is the pitch of #40 roller chain?**

1/2 in (12.70 mm): roller Ø 0.312 in (7.92 mm), inner width 0.312 in (7.92 mm), pin Ø 0.156 in (3.96 mm), plate thickness 0.060 in (1.52 mm).

**What is the pitch of #50, #60 and #80 chain?**

#50 is 5/8 in (15.875 mm), #60 is 3/4 in (19.05 mm), #80 is 1 in (25.40 mm).

**How tall are the plates of #40 chain?**

At most 0.95 × pitch = 0.475 in (12.07 mm) for the roller-link plates (A-Metric prints 0.472 in); the pin-link plates are lower (0.82 P).

**Why do sources disagree on #80 pitch?**

One catalogue prints 1.25 in for #80: that is a typo, ANSI #80 is 1 in (8 × 1/8 in).

## Fits with

- [Roller chain sprockets: #25 (6.35 mm) and #35 (9.525 mm), 10–40 T](https://xemstudio.com/objects/roller-chain-sprockets/)
- [Roller chain sprocket dimensions (ANSI): pitch diameter, outside diameter, caliper and tooth width, #25 to #80, 9 to 60 teeth](https://xemstudio.com/objects/roller-chain-sprocket-dimensions-ansi/)
- [Metric shafts Ø3 to Ø10 with D-flats and clip grooves](https://xemstudio.com/objects/metric-shafts/)
- [Taper-Lock bushings 1008 to 5050: bore range, length through bore, set screw and cap screw sizes](https://xemstudio.com/objects/taper-lock-bushings-1008-to-5050/)
- [QD bushings SH, SDS, SD: length, bolt circle, flange diameter and cap screws](https://xemstudio.com/objects/qd-bushings-sh-sds-sd/)
- [Timing belt profiles: GT2, HTD 3M / 5M / 8M, T5, T10, AT5, MXL, XL, L, H: pitch, tooth height and pulley pitch diameter](https://xemstudio.com/objects/timing-belt-profiles-pitch-and-tooth/)