# 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)

> What are the dimensions of SBR12, SBR16, SBR20, SBR25 and SBR30 supported linear rails and SBR..UU blocks: base width, hole spacing, hole diameter, block holes and thread?

- Category: Hardware › Bearings, rails & motion
- Kind: Standard part
- Basis: WF International, the VEVOR SBR manual and BuildYourCNC (SBR20 only); only values with a clear meaning are shown and the disagreements are listed
- Page: https://xemstudio.com/objects/sbr-supported-rail-linear-guides-sbr12-sbr30/ · JSON: https://xemstudio.com/api/geometry?object=sbr-supported-rail-linear-guides-sbr12-sbr30 · Plain text: https://xemstudio.com/objects/sbr-supported-rail-linear-guides-sbr12-sbr30/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**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

- 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.

## 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 |
|---|---|---|---|---|
| block holes (SBR16UU / SBR20UU / SBR25UU) | B x C = 32 x 30 (M5) / 35 x 35 (M6) / 40 x 40 (M6) mm | carriage plate drilled on the same B x C with clearance for M5 / M6 screws | designed | all |
| rail base width | 40 / 45 / 55 mm for SBR16 / 20 / 25 (32 for SBR12) | slot or ledge in the machine bed the support sits on | designed | all |
| shaft diameter | Ø12 / 16 / 20 / 25 / 30 | SBR..UU open ball bushing bore of the same nominal diameter (linear-ball-bushings-lm-uu-luu) | run | all |

## Sizes

| 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)) | — | — |

## Where the files are

- 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](https://www.wfint.com.tw/Single-Shaft-Rail-1/Single-Shaft-Rail.html) — web — Publisher's page; dimensions are facts
- VEVOR (product manual PDF): [SBR12 to SBR25 rail support and SBRxxUU block dimension tables (column letters not defined in the PDF)](https://cdn.shopify.com/s/files/1/1163/1976/files/Vevor_Linear_Guide_Rail_1683713889306_1683768994342-1730150728997..pdf) — web — Publisher's page; dimensions are facts
- BuildYourCNC: [SBR20 supported rail: guide width 20, base width 45, hole spacing 30.226 across and 150 along, overall height 37](https://buildyourcnc.com/Item/mechanical-rails-linear-guide-rails-20mm) — web — Publisher's page; dimensions are facts

## Questions

**What is the base width of an SBR16 rail?**

40 mm (WF and VEVOR agree), 5 mm thick, shaft Ø16, with holes Ø5.5 (WF) or Ø6 (VEVOR) 30 mm apart across the rail and 150 mm apart along it.

**What are the mounting holes of an SBR20UU block?**

Four M6 holes, 35 x 35 mm (B x C), block 48 wide and 50 long (WF and VEVOR agree).

**Why do the hole spacings differ?**

The two catalogs differ for SBR12, SBR20 and SBR25; BuildYourCNC's SBR20 (30.226 across, 150 along) supports the WF value of 30.

## Fits with

- [Linear shafts Ø3 to Ø25 mm (h6), 100 to 1000 mm long](https://xemstudio.com/objects/linear-shafts-h6/)
- [Linear ball bushings LM..UU and LM..LUU (LM8UU, LM10UU, LM12UU, LM16UU, LM20UU, long LUU): bore, OD, length, ring-groove numbers](https://xemstudio.com/objects/linear-ball-bushings-lm-uu-luu/)
- [Flanged linear bushings LMF, LMK, LMH (and long LUU): bore, OD, length, flange size, bolt circle, hole + counterbore, 6 to 60 mm + STEP/STL (8 to 20 mm)](https://xemstudio.com/objects/flanged-linear-bushings-lmf-lmk-lmh/)
- [LM8UU linear bearing Ø8 × Ø15 × 24](https://xemstudio.com/objects/lm8uu-bearing/)
- [Pillow block KP08 envelope with a 608 pocket](https://xemstudio.com/objects/pillow-block-kp08/)
- [HIWIN HG linear guideway: HGR15 to HGR35 rail (width, height, hole pitch, counterbore) and HGH15CA to HGH35CA / HGW15CC to HGW35CC block dimensions](https://xemstudio.com/objects/hiwin-hg-linear-guideway-hgr-hgh-hgw-15-35/)
- [MGN9, MGN12 and MGN15 rails, 150 to 400 mm](https://xemstudio.com/objects/mgn-rails/)
- [Socket head cap screws, M2–M8 (ISO 4762 / DIN 912)](https://xemstudio.com/objects/socket-head-cap-screws-metric/)