Surface plates, Centres and Headstocks
Alkaline plutonic rock from Sweden and South Africa provides a particularly dense homogeneous microstructure and is therefore exceptionally suitable for the manufacture of measuring devices and machine components. These rocks have naturally aged over millions of years and are hence completely free from internal stresses. They are absolutely rust-free, acid-resistant, non-magnetic and electrically nonconducting.
Only select material that is free of defect, without inclusions and appearances of weathering is used for the ULTRA granite measuring devices. This guarantees a high degree of shape stability and wear resistance.
The following stone types are preferentially used:
Material properties in comparison:
| Properties | Granite | Cast iron |
|---|---|---|
| Coefficient of expansion approx. | 5-7,5 × 10-6 / K | 9-10 × 10-6 / K |
| Heat conductivity | Very low | High |
| Hardness | 6-7 Mohs' scale | 180-190 HB |
| Wear resistance | Very good | Good |
| Geometric fidelity | Excellent | Very good with proper handling |
| Corrosion resistance | Excellent | Good |
| Mechanical stability | Good | Very Good |
Flatness tolerances according to DIN 876
The flatness of the measuring surfaces is calculated based on the following formulas: (for value a, indicate length in mm in the formula)
| Grade | Formula | Grade | Formula |
|---|---|---|---|
| 000 | (1 + a/1000)µ | 1 | (10 + a/100)µ |
| 00 | (2 + a/500)µ | 2 | (20 + a/50)µ |
| 0 | (4 + a/250)µ | 3 | (40 + a/25)µ |
ULTRA granite measuring plates:
We can measure your measuring plates directly on site and issue works or calibration certificates.
Your advantages:
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You save the high packaging and transport costs
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No risk of damages in transit
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Minimum downtime for your measuring plate
Special test units on granite base:
We can supply all types of machine components and special test units for individual applications.