Precision Granite Master Square 12 x 12 x 3 (6 Face | Grade AA)

(Same Day Shipping) - Precision Granite Master Square 12in x 12in x 3in Grade AA, 6-Face (USA Made)

Our 12 x 12 x 3 Precision Granite Master Square is available for immediate shipment, including a protective storage case and calibration certificate. Manufactured in the USA from premium black granite, this Grade AA laboratory-grade master square is designed for the highest levels of accuracy in machine alignment, inspection, and calibration applications. ISO 9001 certification is included with the granite master square.

Need a different sized granite square?
	12 x 12 x 3 14 x 14 x 3 16 x 16 x 3 18 x 18 x 3 24 x 24 x 4

Grade AA Accuracy

This Laboratory Grade AA granite master square provides an overall accuracy of 0.00005 inches.

These squares are particularly valuable when performing machine geometry verification, spindle alignment checks, and preventive maintenance on CNC machining centers.

Built for Precision Measurement

Granite master squares are essential reference standards for verifying:

• Perpendicularity (90° squareness)
• Straightness
• Machine tool alignment
• CNC machine X, Y, and Z axis geometry
• Precision inspection and calibration procedures

With all six faces precision finished, this 6-face configuration provides maximum versatility for setup, measurement, and inspection tasks.

Premium Black Granite Construction

Our master squares are manufactured from dense black granite that offers:

• Exceptional dimensional stability
• Superior wear resistance
• Low moisture absorption
• Resistance to corrosion and rust
• Minimal distortion from temperature and humidity changes

The fine-grain structure and tight porosity of black granite make it an ideal material for long-term precision measurement applications.

Note: Lifting/lightening holes are provided to reduce weight and assist with handling. These holes are not precision surfaces and are not held to dimensional tolerances.

Need a different size? Custom granite master squares are available upon request. Contact us for a quote. 

Other Standard Sizes Available (lead time 1-2 weeks)

• 12 x 12 x 3
• 14 x 14 x 3
• 16 x 16 x 3
• 18 x 18 x 3
• 24 x 24 x 4

Questions? Contact our Granite Specialists for assistance selecting the right granite master square for your application. - 608-949-3414