Check the tool path of your CNC machine with the highest degree of precision. These calibration squares can lay flat to check that the X- and Y-axes of your tool path are at 90°. Or sit them up vertically to confirm the Z-axis is perpendicular. Made of Laboratory Grade AA granite, these squares have the tightest flatness tolerance available for granite. They also come with a calibration certificate traceable to NIST that states they've passed a test for accuracy. Moisture, coolant, and chips won't affect the granite, so they remain accurate even when used inside a milling machine. You can also use them to check the squareness and parallelism of finished workpieces.

They have drilled holes to reduce their weight and make them easy to position.

Machined in pairs, these blocks are precision ground to tolerances thinner than a sheet of paper to give you the flattest and squarest surface for positioning workpieces. Since they are perfectly aligned to one another, they’ll keep your workpieces level and parallel. Also known as 1-2-3 blocks, they're typically used to elevate, support, and align parts for measuring and inspecting. They're made from granite, so they won’t scratch the surface of your workpiece. They also won’t warp when temperatures fluctuate. Unlike metal blocks, these granite blocks are nonmagnetic, so they won’t interfere with sensitive electronic equipment. They come with a certificate of accuracy that's traceable to NIST.

Made in pairs, these inspection V-blocks are precision ground to tight tolerances for straight sides, square corners, and centered grooves. Since their top surfaces are perfectly matched, they keep the centerline of your workpiece level and parallel. These blocks are often used to precisely align round workpieces for measuring or inspecting. They come with a certificate traceable to NIST confirming their accuracy. Unlike metal blocks, these black granite blocks don’t rust or warp from temperature changes. They’re also nonmagnetic, so they won’t interfere with sensitive electronic equipment.

Use these inspection V-blocks to support rods, shafts, and other cylindrical workpieces for precise inspection or measuring tasks. The round surfaces reduce pressure on your workpiece, which helps prevent damage.