QD bushings SH, SDS, SD: length, bolt circle, flange diameter and cap screws — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/qd-bushings-sh-sds-sd/  (sheet CC BY 4.0)
Basis: Martin Sprocket catalog E-1 table (length, bolt circle, cap screws) confirmed per size by product pages for SH, SDS and SD; partial by design
Catalog version: 2026-10-20

Sizes: see table below
- QD (quick-disconnect) is a split tapered bushing with a flange, held by three or four cap screws on a bolt circle (Martin's table). The bushing letters give the size (JA, SH, SDS, SD, SK, SF, E, F, J, M, N, P, W, S); the hub or sheave must be 'QD' for that bushing, and the bore is chosen per shaft.
- Only the three smallest are tabulated, because they are the rows that two sources confirm: Martin's catalog E-1 (page B-4) gives length L and bolt circle; product pages for SH 3/4, SDS 1-5/8 and SD 1-3/16 confirm the bolt circles (2.25, 2.688, 2.687 / 2.688 in), the flange diameters (2.688, 3.188, 3.188 in) and, for SDS (1.375, length through bore) and SD (1.813), the length. SH: Martin L 1.250 against a retailer's overall length of 1-7/32 (1.219): a different length measure; Martin's value is shown.
- SDS cap screw: Martin lists 1/4 × 1-3/8 and one product page lists 1/4 × 1-7/8; both are shown (the SD is 1-7/8). Barrel diameter varies with the bore chosen (for example SD 2.187 in on the 1-3/16 bore, SH 1.871 in on the 3/4 bore) so it is not tabulated.
- Left out: JA, SK, SF, E, F, J, M, N, P, W and S. The Martin table text was read, but the SK length (1.125 in) is inconsistent with the other rows, SF's retailer length (2-1/16 in) differs from Martin's 2.000 in, and W / S screw entries are garbled, so those rows are not published here. Bore ranges and keyseat sizes per bushing were also not read legibly. Use Martin's, Dodge's or TB Wood's current catalogue for those sizes.
- No files: the bushing's taper, flange and barrel profile are not in the tables read, so a bushing file would be invented. For hub design use the maker's CAD (links below).

bushing  length L, in (mm)  bolt circle, in (mm)  cap screws (qty × size)  flange Ø, in (mm)
SH  1.250 (31.8)  2.250 (57.1)  3 × 1/4-20 × 1-3/8  2.688 (68.3)
SDS  1.375 (34.9)  2.688 (68.3)  3 × 1/4-20 × 1-3/8 (product page: 1-7/8)  3.188 (81.0)
SD  1.813 (46.1)  2.688 (68.3)  3 × 1/4-20 × 1-7/8  3.188 (81.0)

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Martin Sprocket: Catalog E-1: QD bushings (page B-4): length L, bolt circle, cap screws for JA to S — web — Publisher's page; dimensions are facts — https://dcngli4g50fhp.cloudfront.net/userfiles/ad/martinsprocket/documents/martin_e_1_catalog.pdf
- Applied Industrial: Martin SH 3/4 QD bushing: barrel 1.871, flange 2.688, bolt circle 2.25, 3 × 1/4-20 × 1-3/8 — web — Publisher's page; dimensions are facts — https://www.applied.com/c-brands/c-martin/sh-3-4/SH-Series-QD-Bushing-0-75-in-Bore/p/100001000
- Applied Industrial: Martin SDS 1-5/8 QD bushing: flange 3.188, bolt circle 2.688, length through bore 1.375, 3 × 1/4 × 1-7/8 — web — Publisher's page; dimensions are facts — https://www.applied.com/c-martin-sds-1-5-8/p/100000978
- Source Atlantic: Martin SD 1-3/16 QD bushing: barrel 2.187, flange 3.188, length 1.813, bolt circle 2.687, 1/4-20 × 1-7/8 — web — Publisher's page; dimensions are facts — https://www.sourceatlantic.ca/Product/SD-1-3-16
- 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=qd-bushings-sh-sds-sd