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For compact axes, how do I choose between narrow MGN and wide MGW miniature guides?

2025-11-23

Narrow MGN guides (for example MGN9H, MGN12H) and wide MGW guides (such as MGW9, MGW12) are both miniature profile rails, but they optimize different directions of moment load:

MGN-H (long block)
The “H" long block version mainly increases the pitching and yawing moment capacity (Mp and My):
- Pitching: front–back nose diving of a cantilever (up/down at the end)
- Yawing: twisting around a vertical axis
  A longer block gives a longer distance between the rolling elements along the rail, which helps when the load tries to tip the carriage forward or backward along the travel direction.
MGW (wide block and rail)
The wide MGW series mainly increases the rolling moment capacity (Mr):
- Rolling: side-to-side tilting of a bed or arm (left/right roll)
  The wider base and block footprint make MGW much stronger against a load that tries to flip the carriage sideways, especially when you only have one rail supporting a bed or arm.

In practice:

If your main concern is a cantilever arm or tool head that “noses down" or “twists" along the travel direction, a long MGN-H block can already provide very good support.
If your main concern is a single-rail bed that wants to “roll" left/right, a wide MGW rail is usually the safer choice.

For many 3D printers, designers use MGN12H on X/Y carriages to control pitching and yawing, and choose MGW9/MGW12 under a single-rail bed where rolling is critical. The final decision should still be checked against the catalog moment ratings (Mp, My, Mr) for your load direction and mounting.

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Solutions Details

For compact axes, how do I choose between narrow MGN and wide MGW miniature guides?

For compact axes, how do I choose between narrow MGN and wide MGW miniature guides?