Mahr Marameter 844 N Self-Centering Bore Gage
Mahr Marameter 844 N Self-Centering Bore Gage
Part #:4474000
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Key Features
- 18–50 mm / .7"–1.96" range
- Self-centering design
- 115 mm measuring depth
- 2 µm error limit
- 0.5 µm repeatability
- Low-expansion Invar construction
- Modular measuring system
- Premium German precision-inspection solution
Overview
The Mahr Marameter 844 N is a higher-end self-centering bore-gaging system for demanding precision inspection, positioned above conventional shop-floor dial bore gages.
Thermal Stability
Its construction uses Invar steel, selected for extremely low thermal expansion, which helps minimize measurement error caused by operator body heat and changes in ambient temperature. On a gage specified to a 2 µm error limit, thermal drift is a first-order concern rather than a footnote.
Measurement and Operation
With a specified error limit of 2 µm and repeatability of 0.5 µm across an 18–50 mm range and 115 mm measuring depth, the 844 N suits inspection tasks where a .0005" shop gage cannot resolve the tolerance. The modular measuring system allows the platform to be configured for specific applications.
Applications
Precision inspection and calibration environments — aerospace, medical, bearing and advanced manufacturing work where bore tolerances are held in microns.

Specifications
| Manufacturer | Mahr |
|---|---|
| Model | Marameter 844 N |
| Part Number | 4474000 |
| Type | Self-centering bore gage |
| Measuring Range | 18–50 mm / .7"–1.96" |
| Measuring Depth | 115 mm |
| Error Limit | 2 µm |
| Repeatability | 0.5 µm |
| Construction | Invar steel (low thermal expansion) |
| System | Modular measuring system |