Granite parallel rulers are precision reference measuring tools crafted from high-quality natural granite. They serve as an ideal reference surface for inspecting instruments, precision tools, and mechanical components. These tools are especially valuable for high-accuracy measurements such as assessing straightness, flatness, and parallelism in workpieces, as well as for equipment installation, machine tool tables, guideways, and precision machining surfaces.
Primarily used to inspect the parallelism and perpendicularity of machine tools or components, granite parallel rulers are widely applied in industrial production and laboratory measurement tasks. Their main mineral composition includes plagioclase, pyroxene, small amounts of olivine and biotite, along with trace magnetite. With a fine structure, uniform texture, and high hardness formed over millions of years, they maintain measurement accuracy even under heavy loads.
These rulers can replace equal-height blocks for parallelism measurements and are typically supplied in matched pairs.
Key Features of Granite Parallel Rulers
High Rigidity & Wear Resistance – Excellent hardness and abrasion resistance ensure long-term accuracy.
Superior Dimensional Stability – Natural aging over geological time eliminates internal stress, resulting in minimal thermal expansion and high measurement precision.
Corrosion & Rust Proof – Immune to acid and alkali corrosion, requiring no oiling, easy to clean, and low maintenance with an extended service life.
Non-Magnetic Surface – Smooth movement during measurement without sticking or friction; unaffected by humidity.
Scratch & Temperature Resistance – Maintains flatness and accuracy even under normal temperature conditions without constant-temperature environments.
Technical Requirements for Granite Parallel Rulers
Defect-Free Working Surface – No cracks, pits, loosened structure, grinding marks, or defects that may affect measurement accuracy.
Natural Color Patterns Allowed – Naturally occurring stripes or color spots are acceptable if not affecting performance.
Non-Working Surface Tolerance – No cracks or large loose areas; minor chips, corner drops, or scratches may be repaired.
Material Quality – Must be made from fine-grained, dense granite.
Hardness Standard – Uniform hardness across the working surface, with a Shore hardness rating of HS70 or higher.
With their outstanding precision, durability, and resistance to wear and corrosion, granite parallel rulers are a reliable choice for precision engineering, manufacturing, and metrology applications worldwide.