MeasurementWhat are granite surface plates and what are they used for in metrology?
In precision measurement, everything starts with a flat, stable reference surface: the granite table. In this guide we explain what granite tables or plates are, why granite is the standard in metrology, and which solutions we carry from the Starrett brand.
What are granite solutions?
The granite surface plate or table is the flat base on which parts and instruments rest for accurate measurement. It is the starting point of almost all dimensional metrology: the height gage, indicators, blocks and the parts to be checked are placed on it. Around the plate there is a whole family of accessories, also made of granite, for building measurement setups.
Why granite and not steel?
Granite is the preferred material for surface plates for several reasons:
- It is very stable: it barely expands with temperature changes, so it keeps its flatness.
- Doesn't rust: unlike steel, it doesn't corrode from moisture.
- No burrs: if it gets scratched or struck, it doesn't raise a burr that alters the surface, as metal does.
- Resists wear: stands up to rough shop use while keeping its accuracy.
The granite solutions we carry
We carry the Starrett granite line: the plate and all its accessories, under the same name you will find on our website:
| Granite solution | What is it for? |
|---|---|
| Surface plates | The flat reference base on which measurements are taken |
| Surface plate stands | They hold the plate at working height |
| Surface plate covers | They protect the plate when it is not in use |
| Five-face master squares | Squareness reference with several faces at 90° |
| Tri-squares | They check squareness at 90° |
| Angle plates | They hold the part at an angle for measuring |
| Straight edges | Straightness reference |
| Granite parallels | Parallelism and part support reference |
| Precision cubes | Squareness and support reference on several faces |
| V-blocks | They support and center round parts |
| Surface plate cleaner | Keeps the surface clean and precise |
| Planekator | Checks the flatness of the plate |
| Repeat-O-Meter | Checks the accuracy and repeatability of the plate |
In summary
- The granite table is the flat reference surface on which measurements are taken
- Granite is stable, does not rust, does not burr and resists wear
- Instruments and the parts to be checked rest on the plate
- We carry Starrett granite plates and accessories
Why buy your measuring equipment at NAT MAC?
We are a Starrett distributor, one of the most prestigious brands in the world of metrology, with more than 54 years of experience in the industry and ISO 9001 certified quality. We advise you on choosing the right equipment for what you need to measure.
- Starrett measuring equipment for dimensional and quality control
- Advice on choosing the right instrument for your part and process
- Hand tools, vision systems, optical comparators, laser measurement, granite and force testing
- Backed by ISO 9001 certified quality
Tell us what you need to measure and with what accuracy, and we'll recommend the right equipment. Request your free quote.
Sources: NAT MAC Measurement catalog; Starrett (metrology catalogs).
