<p><code>MG</code> stands for minature guideway.</p>
<p><code>N</code> signifies <em>narrow</em>, whereas <code>W</code> means <em>wide</em>.</p>
<p>So, there is <code>MGN</code> and <code>MGW</code>. You may also see <code>BMN</code> which is equivalent to <code>MGN</code></p>
<p>The numbers, i.e the <code>9</code> and <code>15</code>, refer to the <em>track width</em>. The widths are: 5 mm; 7 mm; 9 mm; 12 mm, and; 15 mm.</p>
<p>The final letter, i.e. <code>C</code> and <code>H</code>, refer to the <em>length of the block</em>, where <code>C</code> is the shorter version, whereas <code>H</code> denotes the longer elongated block which can distribute the load better (as it contains more bearings). These two lengths of the block can be seen compared, in the image below, which shows (from left to right) track widths of 15, 12, 9 and 7 mm, respectively:</p>
<p><a href="https://i.sstatic.net/358zJ.jpg" rel="noreferrer" title="Diagram of linear rails showing block length"><img src="https://i.sstatic.net/358zJ.jpg" alt="Diagram of linear rails showing block length" title="Diagram of linear rails showing block length" /></a></p>
<p><a href="https://www.aliexpress.com/item/4000825866716.html?spm=a2g0o.detail.1000014.3.8dd51e8eaVCjXI&amp;gps-id=pcDetailBottomMoreOtherSeller&amp;scm=1007.40050.281175.0&amp;scm_id=1007.40050.281175.0&amp;scm-url=1007.40050.281175.0&amp;pvid=9bac72d5-25b9-4efb-ad8e-25ae21a6d0a7&amp;_t=gps-id:pcDetailBottomMoreOtherSeller,scm-url:1007.40050.281175.0,pvid:9bac72d5-25b9-4efb-ad8e-25ae21a6d0a7,tpp_buckets:668%232846%238110%231995&amp;pdp_ext_f=%257B%2522sku_id%2522%253A%252210000008652037746%2522%252C%2522sceneId%2522%253A%252230050%2522%257D&amp;pdp_pi=-1%253B3.28%253B-1%253B-1%2540salePrice%253BGBP%253Brecommend-recommend" rel="noreferrer">Source</a></p>
<p><em>Note that there is an error in the diagram for the 7 mm rails</em> - the lengths of the blocks (22.5 and 30.8 mm) have been, obviously, reversed.</p>
<p>A detailed description of the product code is shown below:</p>
<blockquote>
<p><a href="https://i.sstatic.net/Wnuqh.png" rel="noreferrer" title="Linear rail product code dissection"><img src="https://i.sstatic.net/Wnuqh.png" alt="Linear rail product code dissection" title="Linear rail product code dissection" /></a></p>
</blockquote>
<p>Source: <a href="http://motioncontrolsystems.hiwin.us/Asset/MG-Series-Catalog.pdf" rel="noreferrer">Hiwin</a></p>
<p>The other features of the rails may need to be considered, such as their profile (square or round) and the bearings (cantilever or saddle), amongst other things:</p>
<blockquote>
<p>Your choice includes the profile of the rails, commonly square or round. It involves the kind of bearings, either cantilever or saddle slides, plus the stroke, load, speed, duty cycle, mounting area, and of course the mounting orientation, simply because the saddle could potentially move horizontally, vertically, along a wall mount, or even be inverted.</p>
</blockquote>
<p>Source: <a href="https://sandfieldengineering.com/news/2020/what-is-a-linear-rail/" rel="noreferrer">What is a Linear Rail?</a></p>

CC BY-SA 4.0
2022-04-19T13:02:17.343Z
2022-04-19T20:38:13.460Z
2022-04-19T20:38:13.460Z
Greenonline
<p>In looking at 3D printer motions systems, I've seen linear rails with codes like MGN15H and MGN9C. What do the letters and numbers mean?</p>

<hardware><linear-motion><terminology>
What do linear rail codes mean?
chobok
# What do linear rail codes mean?

(Asked by: username_0 on 2022-04-19)

In looking at 3D printer motions systems, I've seen linear rails with codes like MGN15H and MGN9C. What do the letters and numbers mean?

**Tags:** hardware, linear-motion, terminology

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## 1 answers

### Answer by username_1 on 2022-04-19. Score: 10 | Accepted answer

`MG` stands for minature guideway.

`N` signifies *narrow*, whereas `W` means *wide*.

So, there is `MGN` and `MGW`. You may also see `BMN` which is equivalent to `MGN`

The numbers, i.e the `9` and `15`, refer to the *track width*. The widths are: 5 mm; 7 mm; 9 mm; 12 mm, and; 15 mm.

The final letter, i.e. `C` and `H`, refer to the *length of the block*, where `C` is the shorter version, whereas `H` denotes the longer elongated block which can distribute the load better (as it contains more bearings). These two lengths of the block can be seen compared, in the image below, which shows (from left to right) track widths of 15, 12, 9 and 7 mm, respectively:

[![Diagram of linear rails showing block length](https://i.sstatic.net/358zJ.jpg "Diagram of linear rails showing block length")](https://i.sstatic.net/358zJ.jpg "Diagram of linear rails showing block length")

[Source](https://www.aliexpress.com/item/4000825866716.html?spm=a2g0o.detail.1000014.3.8dd51e8eaVCjXI&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.40050.281175.0&scm_id=1007.40050.281175.0&scm-url=1007.40050.281175.0&pvid=9bac72d5-25b9-4efb-ad8e-25ae21a6d0a7&_t=gps-id:pcDetailBottomMoreOtherSeller,scm-url:1007.40050.281175.0,pvid:9bac72d5-25b9-4efb-ad8e-25ae21a6d0a7,tpp_buckets:668%232846%238110%231995&pdp_ext_f=%257B%2522sku_id%2522%253A%252210000008652037746%2522%252C%2522sceneId%2522%253A%252230050%2522%257D&pdp_pi=-1%253B3.28%253B-1%253B-1%2540salePrice%253BGBP%253Brecommend-recommend)

*Note that there is an error in the diagram for the 7 mm rails* - the lengths of the blocks (22.5 and 30.8 mm) have been, obviously, reversed.

A detailed description of the product code is shown below:

> [![Linear rail product code dissection](https://i.sstatic.net/Wnuqh.png "Linear rail product code dissection")](https://i.sstatic.net/Wnuqh.png "Linear rail product code dissection")

Source: [Hiwin](http://motioncontrolsystems.hiwin.us/Asset/MG-Series-Catalog.pdf)

The other features of the rails may need to be considered, such as their profile (square or round) and the bearings (cantilever or saddle), amongst other things:

> Your choice includes the profile of the rails, commonly square or round. It involves the kind of bearings, either cantilever or saddle slides, plus the stroke, load, speed, duty cycle, mounting area, and of course the mounting orientation, simply because the saddle could potentially move horizontally, vertically, along a wall mount, or even be inverted.

Source: [What is a Linear Rail?](https://sandfieldengineering.com/news/2020/what-is-a-linear-rail/)


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