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Granite Triangular Square
Granite Tri Square



Commonly shortened to Tri-Squares or right angled squares, our precision Triangular Squares are supplied to our highest in-house specifications inspired by national and international standards. Our triangular squares offer a great alternative to a full square for the calibration and inspection of squareness and are provided with weight reducing holes as standard to ensure ease of use, movement and transportation.


Grade 00 - Perfect for laboratories to use as a master when calibrating the squareness of laboratory standards, engineers squares and other measuring equipment. High precision triangular squares are also used for calibrating the X, Y and Z axis of measuring machines such as CMMs and for the setting and accurate inspection of CNC machine tools.  

Grade 0 - Offer the solution for fast and accurate manual inspection of squareness at each stage of manufacture and for final inspections.

OSS TS Grade 00 Tolerances

OSS TS Grade 0 Tolerances

Please also see Master Squares.

All sizes quoted are examples of the stock held by On Site Services (Calibration) Ltd. For more information and prices please contact us.


On Site Services (Calibration) Ltd
10 Cavendish Avenue
NG21 9NQ

Thank you for your enquiry.

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