Granite Triangle Ruler

Granite Triangle Ruler

The Ultimate Reference for Precision Angular Measurement

A Granite Triangle Ruler is a master-grade angular reference tool crafted from high-density granite to provide unparalleled stability,accuracy,and durability for establishing,verifying,and transferring precise 90-degree angles in metrology,quality control,and precision manufacturing applications.Unlike conventional metal squares,granite triangle rulers offer exceptional thermal stability,vibration damping,and wear resistance that ensure consistent accuracy across decades of demanding use.

Material and Construction Excellence

Premium Granite Selection

Each triangle ruler begins with carefully selected high-density black granite(minimum 2.95 g/cm³)known for its exceptional metrological properties:

Dimensional Stability:Thermal expansion coefficient of 5.5-6.5×10⁻⁶/°C ensures minimal dimensional change across temperature variations

Vibration Damping:Natural crystalline structure absorbs vibrational energy,preventing measurement"chatter"

Wear Resistance:Hardness of 6-7 on Mohs scale resists scratching and maintains edge integrity

Non-Magnetic Properties:Eliminates interference with sensitive measuring instruments

Precision Manufacturing Process

Single-Piece Construction:Machined from monolithic granite blocks to ensure uniform material properties

Multi-Stage Lapping:Progressive lapping achieves precise flatness and angular accuracy

Stress-Relief Processing:Extended thermal stabilization prevents future dimensional changes

Edge Hardening:Optional edge treatments enhance durability in high-use applications

Technical Specifications

Standard Accuracy Grades

Grade A(Inspection Grade)

Angular Accuracy:90°±5 arc-seconds

Straightness:±0.00005"per 12"(±0.00125mm/300mm)

Surface Finish:8-16 microinches Ra

Typical Applications:Quality control departments,production inspection

Grade AA(Laboratory Grade)

Angular Accuracy:90°±2 arc-seconds

Straightness:±0.000025"per 12"(±0.00063mm/300mm)

Surface Finish:4-8 microinches Ra

Typical Applications:Calibration laboratories,high-precision manufacturing

Angular Accuracy:90°±1 arc-second

Straightness:±0.000010"per 12"(±0.00025mm/300mm)

Surface Finish:2-4 microinches Ra

Typical Applications:Standards laboratories,primary reference

Standard Size Range

Leg Lengths:150mm(6")to 1000mm(40")with proportional thickness

Thickness:50mm(2")to 150mm(6")depending on length

Weight:Significantly heavier than equivalent steel squares,providing inherent stability

Geometric Features

True 90°Angle:Precision ground and verified

Parallel Edges:Opposite faces parallel within tight tolerances

Reference Surfaces:All working surfaces precision ground

Identification Markings:Laser-etched serial numbers and accuracy grade

Design Features and Variants

Standard Right-Angle Triangle

Classic L-Shape:Traditional design with two perpendicular arms

Equal Leg Options:Legs of equal or unequal lengths

Through-Hole Option:Central hole for handling and mounting

Edge Treatments:Beveled edges for safety and protection

Precision Square with Center Finder

Integrated Center Marks:Precision reference marks at exact center points

Additional Reference Edges:45°angles or other common angles

Mounting Provisions:Threaded inserts for fixture integration

Enhanced Grip Features:Textured or contoured handling areas

Special Application Variants

Extra-Long Triangles:Up to 2000mm(80")for large-scale applications

Ultra-Thin Profiles:For confined space applications

Reinforced Designs:Additional thickness at stress points

Custom Angle Triangles:Non-90°angles for specific applications

Accessory Integration

Magnetic Attachment Points:For securing to ferromagnetic surfaces

Insulated Handles:For temperature isolation during handling

Protective Carrying Cases:Custom-fitted for protection and transport

Verification Certificates:Individual calibration documentation