Laser-Calibrated Precision Granite Straightedge | ±0.5μm/m Accuracy

Laser-Calibrated Precision Granite Straightedge | ±0.5μm/m Accuracy

Precision granite straightedges—also referred to as granite rulers or rock parallel gauges within the precision engineering sector—are critical reference standards in mechanical manufacturing, dimensional metrology, and precision equipment installation.

These instruments demonstrate exceptional dimensional stability, negligible coefficient of thermal expansion, and superior wear resistance—properties attributable to high-density, fine-grained granite sourced exclusively from geologically selected quarries meeting stringent material specifications. Each precision granite straightedge from Shandong Sincere undergoes controlled precision lapping and is calibrated using laser interferometry to achieve the straightness tolerance of ±0.5 μm per meter.

The non-magnetic surface, stable chemical properties, and corrosion resistance of granite ensure accurate measurements in electromagnetic-sensitive or harsh environmental applications. ensures measurement integrity in electromagnetically sensitive or environmentally demanding applications, rendering them particularly suitable for coordinate measuring machine (CMM) calibration, surface plate verification, and high-accuracy optical alignment procedures.

Rigorous Production Process

The manufacturing of the product follows a stringent process chain.

Step 1.Selection of raw blocks: Only “Jinan Black” or “South African Stone” materials from deep-seated veins—free of hidden cracks and impurities—are chosen. Granite exhibits exceptional stability: after hundreds of millions of years of natural aging, internal stresses are completely eliminated, and it remains minimally affected by temperature, showing almost no deformation.

Step 2. Cutting process of diamond: cutting raw materials into rough blanks according to the required size.

Step 3. Multi-stage surface refining: starting from rough grinding, going through intermediate and fine grinding stages, and finally carrying out manual grinding or cnc-assisted polishing, so as to achieve sub-micron working surface flatness.

Step 4.The final quality confirmation needs double independent verification: firstly, the straightness is verified by laser interferometry and high-precision electronic level, and then it completely meets the established requirements of size and precision.