SBR supported linear rails SBR12 to SBR30 and SBR..UU blocks: shaft, base width, hole spacing, hole size, block holes (sources shown where they disagree) — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/sbr-supported-rail-linear-guides-sbr12-sbr30/ (sheet CC BY 4.0) Basis: WF International, the VEVOR SBR manual and BuildYourCNC (SBR20 only); only values with a clear meaning are shown and the disagreements are listed Catalog version: 2026-10-20 Sizes: see table below - SBR rails are a shaft of the stated diameter (a hardened, ground round rail) clamped along its length by an aluminium support with a slot, bolted down through holes in the base; SBR..UU is the matching open linear ball bushing block. The family is a de-facto catalog standard (the same sizes appear as SBR, SBS, TBR and TBS from different makers), not an ISO / DIN standard; makers' tables use their own column letters. - What is shown and why: three sources were read and the page keeps only values with a clear meaning. WF International (Taiwan, labelled table), the VEVOR product manual (the same numbers in a table whose letters are not defined) and BuildYourCNC for SBR20 alone (labelled: base width 45, hole spacing 30.226 across, 150 along). They agree on the shaft sizes and on the base width of the rail support (WF 'W2' = VEVOR 'B' = 32 / 40 / 45 / 55 for SBR12 / 16 / 20 / 25), its thickness (4 / 5 / 5 / 6) and the blocks' W, L, B, C and thread for SBR16UU, SBR20UU and SBR25UU. They disagree on the hole spacing across the rail for SBR12 (23 vs 22), SBR20 (30 vs 35) and SBR25 (35 vs 40), on the hole diameter (Ø4.5 vs Ø5, Ø5.5 vs Ø6 for SBR12 / 16 / 20), and on every SBR12UU number (W 36 vs 40, L 34 vs 39, B 26 vs 28, C 24 vs 26). Both values are shown with their source; BuildYourCNC supports WF on SBR20. - Left out because no source defines the letters or the sources conflict: the rail's overall height and the shaft's centre height (WF's 'H' and 'h', VEVOR's 'h' and 'H' mean different things), the block's height, the SBR30UU numbers beyond WF, and the SBRL (long) blocks. Treat every value above as a catalog-class number and measure the part you have; SBR is sold by many makers without a controlling standard. - Numbers only: nothing here is drawn, because the support profile (slot, root shape) is not published in any of the three sources. - The round shaft alone (unsupported) is on linear-shafts-h6; the blocks' bushings are LM..UU open type on linear-ball-bushings-lm-uu-luu. part shaft / rail size d, mm base width of the rail support, mm width W of the block, mm length L of the block, mm block holes B x C, mm (thread) rail support thickness t, mm / hole spacing across, mm rail hole diameter / hole pitch along, mm SBR12 rail (supported shaft) Ø12 32 — — — t 4; across 23 (WF) / 22 (VEVOR) Ø4.5 (WF) / Ø5 (VEVOR); pitch 100 (WF) SBR16 rail (supported shaft) Ø16 40 — — — t 5; across 30 (WF, VEVOR) Ø5.5 (WF) / Ø6 (VEVOR); pitch 150 (WF) SBR20 rail (supported shaft) Ø20 45 — — — t 5; across 30 (WF, BuildYourCNC 30.226) / 35 (VEVOR) Ø5.5 (WF) / Ø6 (VEVOR); pitch 150 (WF, BuildYourCNC) SBR25 rail (supported shaft) Ø25 55 — — — t 6; across 35 (WF) / 40 (VEVOR) Ø6.5 (WF, VEVOR); pitch 200 (WF) SBR30 rail (supported shaft) Ø30 60 — — — t 7; across 40 (WF) Ø6.5 (WF); pitch 200 (WF) SBR12UU block Ø12 — 36 (WF) / 40 (VEVOR) 34 (WF) / 39 (VEVOR) B 26 (WF) / 28 (VEVOR) x C 24 (WF) / 26 (VEVOR) (M5) — — SBR16UU block Ø16 — 45 45 B 32 x C 30 (M5) — — SBR20UU block Ø20 — 48 50 B 35 x C 35 (M6) — — SBR25UU block Ø25 — 60 65 B 40 x C 40 (M6) — — SBR30UU block Ø30 — 70 (WF) 70 (WF) B 50 (WF) x C 50 (WF) (M8 (WF)) — — Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - WF International (Taiwan maker): Single shaft rail (SBR / SBRL): H, h, W, L1, B, C, S1 and track W2, P1, t2, hole pitch, hole diameter — web — Publisher's page; dimensions are facts — https://www.wfint.com.tw/Single-Shaft-Rail-1/Single-Shaft-Rail.html - VEVOR (product manual PDF): SBR12 to SBR25 rail support and SBRxxUU block dimension tables (column letters not defined in the PDF) — web — Publisher's page; dimensions are facts — https://cdn.shopify.com/s/files/1/1163/1976/files/Vevor_Linear_Guide_Rail_1683713889306_1683768994342-1730150728997..pdf - BuildYourCNC: SBR20 supported rail: guide width 20, base width 45, hole spacing 30.226 across and 150 along, overall height 37 — web — Publisher's page; dimensions are facts — https://buildyourcnc.com/Item/mechanical-rails-linear-guide-rails-20mm 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=sbr-supported-rail-linear-guides-sbr12-sbr30