Precision At Starrett, we understand precision. For generations, the precision that we build into our products has allowed our customers to ensure the quality of their products. Precision is something we take very seriously. Primary St andards To ensure accuracy, manufacturers must enforce strict quality control processes. This starts with applying primary standards for measurement and inspection.This will ultimately lead to consistent, reliable gaging results. Precision gage blocks are the primary standards vital to dimensional quality control in the manufacture of interchangeable parts. These blocks are used for calibrating precision measuring tools and for setting numerous comparative type gages. However, even gage blocks are held to their own level of higher standards: Grand Master Blocks. Accura te Reference Surfaces Every linear measurement depends on an accurate reference surface from which final dimensions are taken. Precision Granite Surface Plates provide the best reference plane for work inspection and layout prior to machining. They are also ideal bases for making height measurements and gaging surfaces, parallelism, etc.A high degree of flatness, stability, overall quality and workmanship also make them ideal bases for mounting sophisticated mechanical, electronic and optical gaging systems. Accuracy Starrett precision measuring tool accuracies are based on their traceability through our grand master gage blocks as certified by the National Institute of Standards and Technology (NIST). Worldwide,no one else has produced the accuracy and stability of Starrett-Webber croblox® Grand Masters. They were produced in 1955 out of chromium carbide material to an accuracy within one millionth of an inch (.0000254mm) and have been checked periodically by the National Bureau of Standards and the National Institute of Standards and Technology (NIST). They have remained stable over this period. 13 starrett.com