Granite Square Flatness and Squareness Inspection Method
A granite square (also known as a granite right angle ruler or engineer's square) is a precision metrology tool designed for checking perpendicularity, ensuring that workpieces and machine components are aligned accurately during manufacturing or assembly. It is also widely used for marking and layout work in industrial workshops.
With high accuracy, stability, and corrosion resistance, granite squares are essential for machine tools, mechanical equipment, CNC machining, and precision engineering.
1. Flatness Inspection of the Granite Square Working Face
Place the granite square securely on a precision granite surface plate with its working face horizontal.
Choose a bridge plate according to the face length (8–10 measuring steps, spacing 50–500 mm).
Mount a 0.001 mm/m precision electronic level on the bridge plate.
Move the bridge plate step-by-step from one end to the other, recording each reading.
The difference between the maximum and minimum readings represents the flatness error.
For 200 mm segments, use a smaller bridge plate (50 mm or 100 mm) and repeat the process.
2. Squareness Inspection of Granite Square Working Faces
Place one working face on the granite surface plate.
Align a dial indicator (0.001 mm resolution) using a standard round bar supported on a granite square box.
Zero the indicator against the first face.
Move the indicator to the second face and record the deviation.
The deviation value indicates the squareness error between the two surfaces.
By using these methods, quality control teams can maintain the accuracy, reliability, and service life of granite squares, ensuring consistent performance in precision measurement tasks.