Granite Solutions

Tri-squares
Granite reference surfaces
Granite solutions are reference surfaces and standards of extremely high flatness and stability. Starrett makes them in Crystal Pink® and Superior Red granite—the latter with the highest quartz content for greater wear resistance—in AA (laboratory), A (inspection) and B (shop) grades.
Granite tri-squares make it possible to check squareness in three planes, ideal for geometric control and for aligning parts and machines.
Main features
High-flatness reference surface
Grades AA (laboratory), A and B
Stable, durable black granite
Brand

Typical applications
- Reference surface for inspection
- Layout and marking base
- Mounting of measuring instruments
- Flatness verification
- Height gage base
- Inspection of machined parts
- Instrument calibration
- Metrology laboratory
- Quality control
Featured products
| Size / Model | Grade | Description |
|---|---|---|
| 200 × 250 mm | A | Granite tri-square, 3 planes. |
| 300 × 400 mm | A | Squareness verification on 3 faces. |
Note: The data shown is for reference only and may vary depending on the model, the manufacturer and the conditions of use.
Related products
Surface platesReference plane for part inspection and layout.
Surface plate standsSteel stands that support and stabilize surface plates.
Surface plate coversCompact surfaces for portable inspection of small parts.
Five-face master squaresX-Y-Z alignment verification on CNC and CMM.
Angle platesVertical workholding for inspection and machining.