Granite surface plates and tables are a must for accurate measurement and provide a flat and stable environment for inspection. They are free from temperature distortion and offer an exceptionally sturdy measuring environment due to their thickness and weight.
Measuring on uneven surfaces can give incorrect or inconsistent inspection results, using a granite surface plate can help eliminate this problem.
Manufactured to the same quality standards made synonymous by Crown since 1904, all Eley granite tables and surface plates conform to BS 817 (2008) and are available in three grades, Grade 0, Grade 1 and Grade 2.
Our granite surface tables are supplied with a high-quality box section support stand for easy levelling with five adjustable points of support; 3 being primary points and the others outriggers for stability.
All granite plates and tables are supported by UKAS Certification.
Why Choose Granite for Machine Bases and Metrology Components
Granite, a type of igneous rock was formed in the Earth millions of years ago. The composition of igneous rock contained many minerals such as quartz that is extremely hard and wear resistant. In addition to hardness and wear resistance granite has approximately half the coefficient of expansion as iron. It is non-magnetic and will not rust. Its volumetric weight is approximately one third that of iron.
Granite is far more cost-effective, cut surfaces can be exceptionally flat. Not only can it be hand lapped to achieve extremes of accuracy but reconditioning can be performed without moving the plate or table off-site. It is entirely a hand lapping operation and generally costs much less than re-conditioning a cast iron alternative.
These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components.
Advantages of Granite Surface Plates
If scratched it will not burr and therefore the plane of the surface is unaffected and will retain its accuracy longer than conventional surfaces.
The surface is a continuous plane, not a series of bearing points, thus giving 2-3 times the life of other materials.
Will not rust or be affected by chemical action. Provides a smooth non-wringing surface over which instruments will easily move.
Has a low coefficient of expansion and is, therefore, less affected by temperature change. This coupled with the natural rigidity of the stone results in unequally.
Granite components are easy to clean and can be resurfaced to original accuracy at low cost and quick turnaround.
Grade 0 - Granite Surface Plates & Tables
Eley Metrology's Granite Surface Plates and Tables are in accordance with BS 817 (2008) and are graded at three levels; Grade 0 plates and tables are typically used for laboratory environments where master artefacts are required.
| GRADE | SIZE (mm) | OVERALL FLATNESS (µm) | LOCAL FLATNESS (µm) |
|---|---|---|---|
| 0 | 300 x 200 x 50 | 3.5 | 3 |
| 0 | 300 x 300 x 50 | 4 | 3 |
| 0 | 450 x 300 x 75 | 4 | 3 |
| 0 | 450 x 450 x 75 | 4.5 | 3 |
| 0 | 600 x 450 x 75 | 4.5 | 3 |
| 0 | 600 x 600 x 75 | 5 | 3 |
| 0 | 900 x 600 x 100 | 5.5 | 3 |
| 0 | 1000 x 1000 x 150 | 5.5 | 3 |
| 0 | 1200 x 900 x 150 | 6.5 | 3 |
| 0 | 1500 x 1000 x 200 | 7.5 | 3 |
| 0 | 1800 x 900 x 200 | 8 | 3 |
| 0 | 2000 x 1200 x 200 | 8 | 3 |
| 0 | 2400 x 1200 x 200 | 9.5 | 3 |
Grade 1 - Granite Surface Plates & Tables
Eley Metrology's Grade 1 plates and tables are most often used for inspection purposes.
| GRADE | SIZE (mm) | OVERALL FLATNESS (µm) | LOCAL FLATNESS (µm) |
|---|---|---|---|
| 1 | 300 x 200 x 50 | 7 | 6 |
| 1 | 300 x 300 x 50 | 8 | 6 |
| 1 | 450 x 300 x 75 | 8 | 6 |
| 1 | 450 x 450 x 75 | 9 | 6 |
| 1 | 600 x 450 x 75 | 9 | 6 |
| 1 | 600 x 600 x 75 | 10 | 6 |
| 1 | 900 x 600 x 100 | 11 | 6 |
| 1 | 1000 x 1000 x 150 | 11 | 6 |
| 1 | 1200 x 900 x 150 | 13 | 6 |
| 1 | 1500 x 1000 x 200 | 15 | 6 |
| 1 | 1800 x 900 x 200 | 16 | 6 |
| 1 | 2000 x 1200 x 200 | 16 | 6 |
| 1 | 2400 x 1200 x 200 | 19 | 6 |
Grade 2 - Granite Surface Plates & Tables
Eley Metrology's Grade 2 surface plates and tables are commonly used in workshop environments where such a high flatness tolerance is not required.
| GRADE | SIZE (mm) | OVERALL FLATNESS (µm) | LOCAL FLATNESS (µm) |
|---|---|---|---|
| 2 | 300 x 200 x 50 | 14 | 12 |
| 2 | 300 x 300 x 50 | 16 | 12 |
| 2 | 450 x 300 x 75 | 16 | 12 |
| 2 | 450 x 450 x 75 | 18 | 12 |
| 2 | 600 x 450 x 75 | 18 | 12 |
| 2 | 600 x 600 x 75 | 20 | 12 |
| 2 | 900 x 600 x 100 | 22 | 12 |
| 2 | 1000 x 1000 x 150 | 22 | 12 |
| 2 | 1200 x 900 x 150 | 26 | 12 |
| 2 | 1500 x 1000 x 200 | 30 | 12 |
| 2 | 1800 x 900 x 200 | 32 | 12 |
| 2 | 2000 x 1200 x 200 | 32 | 12 |
| 2 | 2400 x 1200 x 200 | 38 | 12 |
All Eley Metrology's larger plates (900 x 600 x 100 and up) are available with a high-quality steel support stand as standard with 3 adjustable points to ensure flatness on any surface, these support stands can also be applied to 600 and above size of plate when you require a specific working height.
If any non-standard sizes are required, Eley can produce one-off or 'special' sized granite surface plates and tables to your specifications.
Find Out More
If you’d like more details about our range of Metrology Equipment, then our team are available to help.
Call Us: +44 (0) 1332 367475
Email: sales@eleymet.com
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