Precision Surface Plate

Precision Surface Plate

The Universal Foundation for Dimensional Measurement

A Precision Surface Plate is more than a simple work surface—it is a certified geometric reference artifact that serves as the fundamental datum for all dimensional measurement,inspection,and precision assembly.Engineered to provide an ultra-flat,stable,and repeatable plane,it forms the critical foundation upon which measurement confidence is built across manufacturing,quality control,and research laboratories worldwide.

Material Excellence:The Choice for Ultimate Stability

Granite:The Metrology Standard

The majority of precision surface plates utilize high-density black granite,selected for its exceptional metrological properties:

Superior Vibration Damping:Granite absorbs 10-15 times more vibrational energy than steel or cast iron,eliminating"chatter"during sensitive measurements

Minimal Thermal Expansion:With a coefficient of approximately 6×10⁻⁶/°C(half that of steel),granite maintains dimensional stability across temperature variations

Exceptional Wear Resistance:The hard,non-porous surface resists scratching,denting,and corrosion,ensuring long-term accuracy

Non-Magnetic&Electrically Neutral:Eliminates interference with sensitive measuring instruments

Alternative Materials for Specialized Applications

Cast Iron:Used where magnetic properties are required for holding fixtures,though with lower vibration damping

Glass Ceramic:For ultra-high precision applications requiring near-zero thermal expansion

Steel-Reinforced Composite:For extreme load applications where granite's compressive strength requires enhancement

Accuracy Grades:Matching Precision to Purpose

Precision surface plates are classified into standardized grades,each serving distinct accuracy requirements:

Grade B(Toolroom Grade)

Flatness Tolerance:±0.0001"per foot(±0.0025mm/m)

Typical Applications:Machine shop layout,welding fixture foundations,general assembly reference

Surface Finish:8-16 microinches Ra

Primary Use:Where flatness is helpful but not critically measured

Grade A(Inspection Grade)

Flatness Tolerance:±0.00005"per foot(±0.00125mm/m)

Typical Applications:Quality control departments,production inspection,general metrology

Surface Finish:4-8 microinches Ra

Primary Use:The workhorse grade for manufacturing quality assurance

Grade AA(Laboratory Grade)

Flatness Tolerance:±0.000025"per foot(±0.00063mm/m)

Typical Applications:Calibration laboratories,high-precision manufacturing,optical alignment

Surface Finish:2-4 microinches Ra

Primary Use:Where measurement uncertainty must be minimized

Flatness Tolerance:±0.00001"per foot(±0.00025mm/m)or better

Typical Applications:National standards laboratories,primary reference standards,semiconductor manufacturing

Surface Finish:1-2 microinches Ra

Primary Use:Establishing and transferring primary measurement standards