Woodruff keys, inch (ANSI B17.2): key numbers #202 to #1212, key sizes and keyseat depths — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/woodruff-keys-inch-ansi-b17-2/ (sheet CC BY 4.0) Basis: ANSI B17.2 tables as published by Engineers Edge, column meanings from AmesWeb, W × B / length / height checked against McMaster-Carr Catalog version: 2026-10-20 Sizes: see table below - A Woodruff key is a segment of a disc: a round bottom that sits in a seat cut with a woodruff cutter, and a flat top. The key number codes the size: the last two digits are the disc diameter B in eighths of an inch, the digits before them are the width W in thirty-seconds. Key No. 404 is 4/32 × 4/8 = 1/8 × 1/2 in; No. 1212 is 12/32 × 12/8 = 3/8 × 1-1/2 in. Nos. 202.5 and 302.5 carry a half-eighth: 5/16 in diameter. - Files: for each of the 41 key numbers, one key solid and one example shaft with its keyseat. The key is the part of a disc of diameter B that lies below a flat chord E under the disc centre, so its height is B/2 − E. That reproduces the printed length F (the chord) and the printed height C for all 41 sizes. Two heights are printed (C and D); the files use C. McMaster's listing gives D as the key height; the two differ by at most 0.009 in. - The seat is a circle of the cutter diameter (modelled at the nominal B; the table gives the cutter range F min – max), the nominal key width wide, with its bottom at the published depth B below the top line of the shaft, measured along the seat centre line. Depth tolerance +.005 / −0. Shaft diameter is not tied to the key in the tables used here, so the example shafts in the files are the same diameter as the key disc; pick the key for your shaft from the maker's selection guidance and treat the example diameter as a placeholder. - Cross-checks: shaft depth + key above shaft = the minimum key height C; shaft depth + hub depth = the maximum C (to within 0.001 in). Key width, diameter, length and D height of all 41 keys agree with McMaster's key listing. Length tolerance +.000 / −.010 in. Hub seat depth tolerance +.005 / −0; hub width +.002 / −0. - Left out: the longer keys (Nos. 617 to 2428, 2-1/8 to 3-1/2 in diameter), which only the keyseat table lists, with no key-height table or second source to check them; shaft-diameter ranges per key, which neither source prints; edge chamfers or radii, which the tables do not give. key no. nominal W × B, in key length F, in height C max / min, in height D max / min, in flat below centre E, in shaft seat width A min – max, in shaft seat depth B, in cutter diameter F min – max, in key above shaft C, in hub seat width D, in hub seat depth E, in 202 1/16 × 1/4 0.248 0.109 / 0.104 0.109 / 0.104 1/64 0.0615 – 0.0630 0.0728 0.250 – 0.268 0.0312 0.0635 0.0372 202.5 1/16 × 5/16 0.311 0.140 / 0.135 0.140 / 0.135 1/64 0.0615 – 0.0630 0.1038 0.312 – 0.330 0.0312 0.0635 0.0372 302.5 3/32 × 5/16 0.311 0.140 / 0.135 0.140 / 0.135 1/64 0.0928 – 0.0943 0.0882 0.312 – 0.330 0.0469 0.0948 0.0529 203 1/16 × 3/8 0.374 0.172 / 0.167 0.172 / 0.167 1/64 0.0615 – 0.0630 0.1358 0.375 – 0.393 0.0312 0.0635 0.0372 303 3/32 × 3/8 0.374 0.172 / 0.167 0.172 / 0.167 1/64 0.0928 – 0.0943 0.1202 0.375 – 0.393 0.0469 0.0948 0.0529 403 1/8 × 3/8 0.374 0.172 / 0.167 0.172 / 0.167 1/64 0.1240 – 0.1255 0.1045 0.375 – 0.393 0.0625 0.1260 0.0685 204 1/16 × 1/2 0.491 0.203 / 0.198 0.194 / 0.188 3/64 0.0615 – 0.0630 0.1668 0.500 – 0.518 0.0312 0.0635 0.0372 304 3/32 × 1/2 0.491 0.203 / 0.198 0.194 / 0.188 3/64 0.0928 – 0.0943 0.1511 0.500 – 0.518 0.0469 0.0948 0.0529 404 1/8 × 1/2 0.491 0.203 / 0.198 0.194 / 0.188 3/64 0.1240 – 0.1255 0.1355 0.500 – 0.518 0.0625 0.1260 0.0685 305 3/32 × 5/8 0.612 0.250 / 0.245 0.240 / 0.234 1/16 0.0928 – 0.0943 0.1981 0.625 – 0.643 0.0469 0.0948 0.0529 405 1/8 × 5/8 0.612 0.250 / 0.245 0.240 / 0.234 1/16 0.1240 – 0.1255 0.1825 0.625 – 0.643 0.0625 0.1260 0.0685 505 5/32 × 5/8 0.612 0.250 / 0.245 0.240 / 0.234 1/16 0.1553 – 0.1568 0.1669 0.625 – 0.643 0.0781 0.1573 0.0841 605 3/16 × 5/8 0.612 0.250 / 0.245 0.240 / 0.234 1/16 0.1863 – 0.1880 0.1513 0.625 – 0.643 0.0937 0.1885 0.0997 406 1/8 × 3/4 0.740 0.313 / 0.308 0.303 / 0.297 1/16 0.1240 – 0.1255 0.2455 0.750 – 0.768 0.0625 0.1260 0.0685 506 5/32 × 3/4 0.740 0.313 / 0.308 0.303 / 0.297 1/16 0.1553 – 0.1568 0.2299 0.750 – 0.768 0.0781 0.1573 0.0841 606 3/16 × 3/4 0.740 0.313 / 0.308 0.303 / 0.297 1/16 0.1863 – 0.1880 0.2143 0.750 – 0.768 0.0937 0.1885 0.0997 806 1/4 × 3/4 0.740 0.313 / 0.308 0.303 / 0.297 1/16 0.2487 – 0.2505 0.1830 0.750 – 0.768 0.1250 0.2510 0.1310 507 5/32 × 7/8 0.866 0.375 / 0.370 0.365 / 0.359 1/16 0.1553 – 0.1568 0.2919 0.875 – 0.895 0.0781 0.1573 0.0841 607 3/16 × 7/8 0.866 0.375 / 0.370 0.365 / 0.359 1/16 0.1863 – 0.1880 0.2763 0.875 – 0.895 0.0937 0.1885 0.0997 707 7/32 × 7/8 0.866 0.375 / 0.370 0.365 / 0.359 1/16 0.2175 – 0.2193 0.2607 0.875 – 0.895 0.1093 0.2198 0.1153 807 1/4 × 7/8 0.866 0.375 / 0.370 0.365 / 0.359 1/16 0.2487 – 0.2505 0.2450 0.875 – 0.895 0.1250 0.2510 0.1310 608 3/16 × 1 0.992 0.438 / 0.433 0.428 / 0.422 1/16 0.1863 – 0.1880 0.3393 1.000 – 1.020 0.0937 0.1885 0.0997 708 7/32 × 1 0.992 0.438 / 0.433 0.428 / 0.422 1/16 0.2175 – 0.2193 0.3237 1.000 – 1.020 0.1093 0.2198 0.1153 808 1/4 × 1 0.992 0.438 / 0.433 0.428 / 0.422 1/16 0.2487 – 0.2505 0.3080 1.000 – 1.020 0.1250 0.2510 0.1310 1008 5/16 × 1 0.992 0.438 / 0.433 0.428 / 0.422 1/16 0.3111 – 0.3130 0.2768 1.000 – 1.020 0.1562 0.3135 0.1622 1208 3/8 × 1 0.992 0.438 / 0.433 0.428 / 0.422 1/16 0.3735 – 0.3755 0.2455 1.000 – 1.020 0.1875 0.3760 0.1935 609 3/16 × 1-1/8 1.114 0.484 / 0.479 0.475 / 0.469 5/64 0.1863 – 0.1880 0.3853 1.125 – 1.145 0.0937 0.1885 0.0997 709 7/32 × 1-1/8 1.114 0.484 / 0.479 0.475 / 0.469 5/64 0.2175 – 0.2193 0.3697 1.125 – 1.145 0.1093 0.2198 0.1153 809 1/4 × 1-1/8 1.114 0.484 / 0.479 0.475 / 0.469 5/64 0.2487 – 0.2505 0.3540 1.125 – 1.145 0.1250 0.2510 0.1310 1009 5/16 × 1-1/8 1.114 0.484 / 0.479 0.475 / 0.469 5/64 0.3111 – 0.3130 0.3228 1.125 – 1.145 0.1562 0.3135 0.1622 610 3/16 × 1-1/4 1.240 0.547 / 0.542 0.537 / 0.531 5/64 0.1863 – 0.1880 0.4483 1.250 – 1.273 0.0937 0.1885 0.0997 710 7/32 × 1-1/4 1.240 0.547 / 0.542 0.537 / 0.531 5/64 0.2175 – 0.2193 0.4327 1.250 – 1.273 0.1093 0.2198 0.1153 810 1/4 × 1-1/4 1.240 0.547 / 0.542 0.537 / 0.531 5/64 0.2487 – 0.2505 0.4170 1.250 – 1.273 0.1250 0.2510 0.1310 1010 5/16 × 1-1/4 1.240 0.547 / 0.542 0.537 / 0.531 5/64 0.3111 – 0.3130 0.3858 1.250 – 1.273 0.1562 0.3135 0.1622 1210 3/8 × 1-1/4 1.240 0.547 / 0.542 0.537 / 0.531 5/64 0.3735 – 0.3755 0.3545 1.250 – 1.273 0.1875 0.3760 0.1935 811 1/4 × 1-3/8 1.362 0.594 / 0.589 0.584 / 0.578 3/32 0.2487 – 0.2505 0.4640 1.375 – 1.398 0.1250 0.2510 0.1310 1011 5/16 × 1-3/8 1.362 0.594 / 0.589 0.584 / 0.578 3/32 0.3111 – 0.3130 0.4328 1.375 – 1.398 0.1562 0.3135 0.1622 1211 3/8 × 1-3/8 1.362 0.594 / 0.589 0.584 / 0.578 3/32 0.3735 – 0.3755 0.4015 1.375 – 1.398 0.1875 0.3760 0.1935 812 1/4 × 1-1/2 1.484 0.641 / 0.636 0.631 / 0.625 7/64 0.2487 – 0.2505 0.5110 1.500 – 1.523 0.1250 0.2510 0.1310 1012 5/16 × 1-1/2 1.484 0.641 / 0.636 0.631 / 0.625 7/64 0.3111 – 0.3130 0.4798 1.500 – 1.523 0.1562 0.3135 0.1622 1212 3/8 × 1-1/2 1.484 0.641 / 0.636 0.631 / 0.625 7/64 0.3735 – 0.3755 0.4485 1.500 – 1.523 0.1875 0.3760 0.1935 Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - Engineers Edge: ANSI Standard Woodruff Key Size Table Chart, ANSI B17.2-1967 (R1998) — web — Publisher's page; dimensions are facts — https://host.engineersedge.com/woodruff_keys.htm - Engineers Edge: Keyseat dimensions for Woodruff keys (ANSI B17.2) — web — Publisher's page; dimensions are facts — https://ns1.engineersedge.com/hardware/keyseat_dimensions_for_woodruff_keys_15008.htm - AmesWeb: Woodruff key sizes and dimensions (ASME B17.2): key number coding, length tolerance — web — Publisher's page; dimensions are facts — https://amesweb.info/Keys/Woodruff-Key-Sizes-Dimensions.aspx - AmesWeb: Woodruff keyseat dimensions and tolerances (ASME B17.2): column meanings, tolerances — web — Publisher's page; dimensions are facts — https://amesweb.info/Keys/Woodruff-Keyseat-Dimensions.aspx - McMaster-Carr: Woodruff keys: inch key sizes (width, diameter, height, length) and metric sizes — web — Publisher's page; dimensions are facts — https://www.mcmaster.com/keys/key-type~woodruff/ Free files (CC BY 4.0, Xem Studio; STEP + STL, 41 parts): https://xemstudio.com/files/hardware/woodruff-keys-inch-ansi-b17-2/index.json API: https://xemstudio.com/api/geometry?object=woodruff-keys-inch-ansi-b17-2