Four-Face Granite Tri-Squares provide an excellent, economical way for accurately checking the X-Y-Z axes on CNC machine tools and coordinate measuring machines. Lying in the horizontal position, the X and Y axes can be checked for 90º squareness. With the square in the vertical position, tracing along the vertical edge of the square can check the perpendicularity of the Z axis. 

Granite tri-squares may also be used in the same manner that steel squares would be used for the direct checking of squareness and straightness.

Granite Tri-Squares - AA Grade - 4-Face at

4-Face Granite Tri-Squares include 2 large faces along with 2 edges that are flat and square to each other, and also includes lightening holes. The number of lightening holes included will vary with the size of the square.

These Granite Tri-Squares are made of black granite, which is stronger and denser than light colored granite, and is also more stable, providing more accurate and more repeatable measurements.

These 4-Face Granite Tri-Squares are available in 2 Grades...

  • AA Grade is also known as Laboratory Grade
  • .000050" Accuracy
  • A Grade is also known as Inspection Grade
  • .0001" Accuracy

Each Tri-Square includes a Certificate of Calibration Traceable to NIST.

  • An ISO 17025 Accredited Cert is available at an extra charge.

sHOP our GRANITE TRI-SQUARES - AA GRADE - 4-FACE collection...

6 products