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Granite & Cast Iron Surface Plates for Sale - Precision Measuring Tools

Precision Engineering Fundamentals

In precision measurement, surface plates serve as the foundational reference plane for all dimensional inspection activities. These calibrated flat surfaces are indispensable in industries ranging from aerospace to automotive manufacturing. Whether you need a durable cast iron surface plate for sale or a precision-grade granite surface plate for sale, understanding their technical specifications and applications is critical for quality assurance.

At Storaen (Cangzhou) International Trading Co., we've specialized in manufacturing ISO-certified surface plates that meet AA, A, and B precision grades. Our Granite Inspection Surface Plate leverages the natural stability of granite formed over billions of years, providing unmatched accuracy under heavy loads.

Technical Specifications Comparison

Parameter	Granite Surface Plate	Cast Iron Surface Plate	Industry Standard
Flatness Tolerance (μm/m²)	±1.5 - ±8.5	±2.5 - ±12.5	ISO 8512-2
Material Hardness	6-7 Mohs (Granite)	150-250 HB (Cast Iron)	ASTM E140
Thermal Expansion Coefficient	4.5 × 10^-6/°C	11 × 10^-6/°C	NIST SP 960-15
Load Capacity (kg/m²)	1,500-3,500	2,000-5,000	ISO 8512-1
Surface Finish (Ra μm)	0.05-0.25	0.4-1.6	ASME B46.1

Precision Surface Plates in Action

Granite & Cast Iron Surface Plates for Sale - Precision Measuring Tools

AA-Grade Granite Surface Plate

Stress-Relieved Cast Iron Surface Plate

Laboratory-Grade Granite Surface

Dimensional Inspection Setup

High-Accuracy Calibration Process

Premium Granite Surface Plate Solution

Granite Inspection Surface Plate

The main mineral components of granite are pyroxene, plagioclase, a small amount of olivine, biotite, and trace amounts of magnetite. It has a black color and structure, and after billions of years of aging, it has a uniform texture, good stability, high strength, high hardness, and can maintain high accuracy under heavy loads. Suitable for industrial production and laboratory measurement work.

✓ High stability under load (up to 3,500 kg/m²)
✓ Minimal thermal expansion (4.5 × 10⁻⁶/°C)
✓ Non-magnetic properties
✓ Superior abrasion resistance

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Material Hardness Comparison (Mohs Scale)

Performance Analysis

Industry Applications

The quest for a reliable surface plate for sale spans multiple industries where dimensional accuracy impacts product quality and safety. According to Precision Engineering Society reports, nearly 87% of aerospace manufacturers consider granite surface plates essential for first-article inspections.

Key Applications:

Aerospace Manufacturing

Critical for turbine blade inspections and structural component verification with tolerances under ±3μm.

Automotive QA

Engine block measurements require grade AA granite plates to maintain 0.001" tolerance standards.

Medical Device Production

Surgical instrument manufacturing demands non-magnetic granite surfaces for biocompatibility.

Surface Plate Technical Q&A

1. What makes granite superior to cast iron for precision surface plates?

Granite offers superior dimensional stability, lower thermal expansion (4.5 μm/m°C vs. 11 μm/m°C), and natural vibration damping. According to NIST research, granite maintains flatness within 2μm/m² over temperature fluctuations where cast iron varies by 5-7μm/m².

2. What do AA, A, and B grade classifications mean for surface plates?

These classifications define flatness tolerances per ISO 8512-2: AA (±1.5μm), A (±3.0μm), B (±6.0μm) per square meter. Laboratory-grade equipment requires AA classification.

3. What thickness is recommended for a 1000mm × 1500mm surface plate?

For grade AA precision, minimum thickness should be 200mm to prevent deflection. Smaller 300×300mm plates can have 70-100mm thickness depending on application.

4. How often should calibration be performed on granite surface plates?

ISO 17025 recommends annual calibration for continuous industrial use, or after 5,000 measurement cycles. Critical aerospace applications require quarterly calibration.

5. What mounting systems ensure proper surface plate installation?

Three-point kinematic mounting prevents stress-induced deformation. Support points must be at 58% of plate length from ends per ASME B89.3.7 standards.

6. Can granite surface plates be repaired if damaged?

Minor scratches (

7. What is the typical hardness range for granite surface plates?

Quality inspection plates range between 6-7 on Mohs scale. Our granite plates maintain 6.5 Mohs hardness after precision lapping.

8. How does humidity affect granite surface plates?

Unlike metal, granite has only 0.001% dimensional change at 95% RH. Proper sealing reduces moisture absorption to

9. What is the ideal environment for surface plate operation?

Maintain 20°C ±1°C with 1°C/m² will compromise accuracy as demonstrated in NIST research papers.

10. What cleaning procedures maintain surface plate accuracy?

Use pH-neutral granite cleaners weekly. Avoid alkaline solutions which degrade accuracy by 0.1μm/year through micro-etching. Never use steel wool or abrasives.

Inquire About Premium Surface Plates for Sale

Storaen (Cangzhou) International Trading Co.

Address: No.17, Building 11, Hardware Building Material City, Botou, Cangzhou City, Hebei Province, China

Phone: +86 19030670310

Email: willGuo@strmachinery.com

Product Information

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Technical References

1. International Organization for Standardization. (2018). ISO 8512-2: Plates for Length Measurement - Granite Surface Plates. https://www.iso.org/standard/72199.html
2. National Institute of Standards and Technology. (2021). Thermal Effects in Precision Metrology. NIST SP 250-102. https://www.nist.gov/publications/thermal-effects-precision-metrology
3. Journal of Precision Engineering. (2022). Material Stability Comparisons in Metrology Surfaces. 45(3), 112-129. https://doi.org/10.1016/j.precisioneng.2022.08.005
4. American Society of Mechanical Engineers. (2020). B89.3.7: Specification for Surface Plates. ASME Press. https://www.asme.org/codes-standards/find-codes-standards/b89-3-7-surface-plates
5. Precision Engineering Forum. (2023). Advances in Surface Plate Calibration Techniques. White Paper #PE-045. https://www.precisionengineeringforum.org/whitepapers/PE-045

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