# HIWIN MGN12H miniature linear guide block: 27 × 45.4 body, M3 20 × 20 holes and rail interface

> What are the HIWIN MGN12H block dimensions and mounting-hole positions?

- Category: Hardware › Bearings, rails & motion
- Kind: Modern device
- Basis: HIWIN Linear Guideway catalogue, MGN series tables for the MGN12 block and MGNR12R rail.
- Page: https://xemstudio.com/objects/hiwin-mgn12h-linear-guide-block/ · JSON: https://xemstudio.com/api/geometry?object=hiwin-mgn12h-linear-guide-block · Plain text: https://xemstudio.com/objects/hiwin-mgn12h-linear-guide-block/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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## Overall (mm)

| length | width | height |
|---|---|---|
| 45.4 | 27.0 | 10.0 |

**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

- Datum: block centre; block underside at 0, top mounting face at 10.0. In assembly the underside is H1 3.0 above the rail bottom and the top face H 13.0 above it.
- Block width W 27.0, overall length L 45.4 including end caps and seals (steel body L1 32.4).
- Four M3 × 3.5 deep tapped holes in the top face on B × C = 20 × 20, centred on the block (modelled Ø2.5 tap drill).
- Underside rail channel 12.0 wide × 5.0 tall along the full length. Mating rail MGNR12R: width 12, height 8.0, M3 cap screws in Ø6.0 × 4.5 counterbores with Ø3.5 through holes at pitch 25.
- Not modelled: end-seal and end-cap profile, the Ø2 lube hole, ball grooves and retainer, and the rail.
- Dimensions are exact nominal (true size), no tolerance added.

## 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 |
|---|---|---|---|---|
| top mounting holes | 4 × M3 on 20 × 20, 3.5 deep | carriage plate M3 screws (at most 3.5 mm engagement) | designed | all |
| rail channel | 12.0 wide, top face 13.0 above the rail bottom | MGNR12R rail | run | all |

## Sizes

| hole | x (mm) | y (mm) | thread |
|---|---|---|---|
| 1 | −10.0 | −10.0 | M3 × 3.5 |
| 2 | +10.0 | −10.0 | M3 × 3.5 |
| 3 | −10.0 | +10.0 | M3 × 3.5 |
| 4 | +10.0 | +10.0 | M3 × 3.5 |

## Where the files are

- HIWIN (catalogue via DAMENCNC): [HIWIN MGN and MGW Product Catalog 2023](https://damencnc.com/userdata/file/3455-3_HIWIN_MGN_and_MGW_Product_Catalog_2023.pdf) — web — Publisher's page; dimensions are facts
- HIWIN (catalogue via Motion USA): [HIWIN MG Series 2025](https://s3.amazonaws.com/www.motionusa.com/hiwin/2025/MG%20Series-2025.pdf) — web — Publisher's page; dimensions are facts

## Free STEP/STL (1 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/hiwin-mgn12h-linear-guide-block/index.json

- hiwin-mgn12h-linear-guide-block: [STEP](https://xemstudio.com/files/hardware/hiwin-mgn12h-linear-guide-block/hiwin-mgn12h-linear-guide-block.step) · [STL](https://xemstudio.com/files/hardware/hiwin-mgn12h-linear-guide-block/hiwin-mgn12h-linear-guide-block.stl) — HIWIN MGN12H miniature linear guide block: 27 × 45.4 body, M3 20 × 20 holes and rail interface

## Questions

**What is the MGN12H mounting-hole pattern?**

Four M3 holes, 3.5 mm deep, on a 20 × 20 mm square centred on the block.

**How tall is an MGN12H on its rail?**

13.0 mm from the rail bottom to the block top (block underside 3.0 mm above the rail bottom).

**How long is the MGN12H?**

45.4 mm including end caps and seals; the steel body is 32.4 mm. Width 27.0 mm.

## Fits with

- [HIWIN MGN miniature linear guideway: MGNR5, 7, 9, 12, 15 rails and MGN7, 9, 12, 15 C / H blocks (width, height, hole pitch, counterbore, mounting holes)](https://xemstudio.com/objects/hiwin-mgn-miniature-guideway-mgn5-mgn15/)
- [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/)
- [2020 aluminum extrusion, 6 mm slot (20-series)](https://xemstudio.com/objects/2020-aluminum-extrusion/)
- [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/)