Use the Starrett gauge blocks in these sets individually or together to take precise measurements or calibrate your measuring tools. They are often used to mark layouts, align machine components, and check that parts are within tolerance. All have been laboratory calibrated and include NIST traceable certification with the tested measurements. The blocks are individually numbered for recalibration.

Each block has a grade per ASME B89.1.9. Grades are based on tolerance—the smaller the tolerance, the greater the accuracy. Grade 0 means these gauge blocks are our most accurate. They help verify that precise measuring instruments, such as micrometers and calipers, are taking accurate readings.

Use a gauge block holder (not included) to create a custom repeatable measurement by stacking multiple blocks together. To prevent your gauge block combinations from wearing down over time, add wear blocks (not included) on each end.

Square blocks have a hole that runs through their center. Stack multiple square blocks together and secure them with a rod (not included).

Steel blocks are the most common choice.