When you purchase a Starrett Tru-Stone Granite Surface Plate, you have made investment in the best, most stable reference surface available – the necessary starting point of an accurate surface-based measurement. Here is an overview of factors that will allow you to get many years of reliable service from your investment.
 
How can I reduce wear and extend the life of my surface plate?
First, it is important to keep the plate clean. Airborne abrasive dust is usually the greatest source of wear and tear on a plate, as it tends to embed in work pieces and the contact surfaces of gages.

It is also very important cover your plate to protect it from dust and damage. Wear life can be extended by covering the plate when not in use. Starrett offers a range of covers specifically for our surface plates.

Rotate the plate periodically so that a single area does not receive excessive use

Replacing steel contact pads on gauging with carbide pads.

Avoid setting food or soft drinks on the plate. Many soft drinks contain either carbonic or phosphoric acid, which can dissolve the softer minerals and leave small pits in the surface.

How often should I clean my surface plate?
This depends on how the plate is being used. If possible, we recommend cleaning the plate at the beginning of the day (or work shift) and again at the end. If the plate becomes soiled, particularly with oily or sticky fluids, it should probably be cleaned immediately.

Clean the plate regularly with Starrett Surface Plate Cleaner (32 oz bottle: EDP: 81824). The choice of cleaning solutions is important. If a volatile solvent is used (acetone, lacquer thinner, alcohol, etc.) the evaporation will chill the surface, and distort it. In this case, it is necessary to allow the plate to normalize before using it or measurement errors will occur.



After Cleaning
The amount of time required for the plate to normalize after cleaning will vary with the size of the plate, and the amount of chilling. An hour should be sufficient for smaller plates. Two hours may be needed for larger plates. If a water-based cleaner is used, there will also be some evaporative chilling.

The plate will also retain the water, and this could cause rusting of metal parts in contact with the surface. Some cleaners will also leave a sticky residue after they dry, which will attract airborne dust, and actually increase wear, rather than decreasing it.

How often should a surface plate be calibrated?
This too depends on the plate usage and environment. We recommend that a new plate or precision granite accessory receive a full recalibration within one year of purchase. If the plate is going to receive heavy use, it is advisable to shorten this interval to six months.

Monthly inspection for repeat measurement errors using a Starrett Repeat Reading Gage (EDP 81815) will show any developing wear spots and only takes a few minutes to perform. After the results of the first recalibration are known, the calibration interval may be extended, or shortened as allowed or required by your internal quality system.

A Starrett Tru-Stone Granite Surface Plate is a significant and important investment. Follow these simple guidelines and it will last for many years.

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