Q: What are granite measuring tools? What are the main types?

A: Granite measuring tools refer to precision measurement reference instruments crafted from natural granite (such as Jinan Green or black granite) leveraging its high stability and hardness. The main types include:
• Granite Surface Plate: The most fundamental reference plane.
• Granite Square Box: Used for measuring perpendicularity.
• Granite Straight Edge: Used for measuring straightness.
• Granite V-Block: Used for supporting cylindrical workpieces.

Q:Why is granite the preferred material for precision measurement?

A: Compared to cast iron, granite offers the following advantages:
• Excellent stability: Extremely low internal stress, minimal deformation over extended periods.
• High hardness: Superior wear resistance, resistant to scratches.
• Corrosion resistance: Unaffected by cutting fluids, oil, or rust.
• Non-magnetic: Suitable for measuring magnetic materials without magnetic field interference.
• Low thermal expansion coefficient: Minimally affected by temperature fluctuations.

Q: What environmental conditions are required when using granite measuring tools?

A: Precision measurement is highly sensitive to environmental factors:
• Temperature: Standard measurement temperature is 20°C. Significant temperature variations cause thermal expansion/contraction, affecting accuracy.
• Humidity: Maintain dry conditions. While granite does not rust, excessive humidity may cause workpiece corrosion or surface condensation on the gauge.
• Vibration: Install on a stable foundation, away from vibration sources like punch presses or forging equipment.
• Light exposure: Avoid direct sunlight to prevent localized thermal deformation.

Q: How should minor burrs or scratches on the surface be addressed?

A: 

• Minor burrs: Gently remove using a natural oilstone (e.g., Arkansas oilstone) dipped in oil. Do not apply excessive force.
• Deep scratches or pits: Do not attempt DIY repair. Contact the manufacturer for professional grinding restoration or recalibration. If located in non-working areas (edges), temporarily avoid using those sections.

Q: What is the calibration cycle?

A: 

• General recommendation: Calibrate annually.
• High-frequency use: Calibrate every 6 months.
• Special circumstances: Immediately recalibrate if the plate is impacted, relocated, or exhibits abnormal measurement fluctuations.

Q: What is the service life of granite measuring tools?

A: 

• With proper use and maintenance, the physical lifespan of granite gauges can exceed 10 years or longer.
• Their “accuracy lifespan” depends on usage frequency and maintenance. Grade 00 flat plates may maintain precision for years in laboratory environments, but may require restoration within 1-2 years under harsh workshop conditions.