A true source of measurement, use these gauge blocks to calibrate measuring equipment, mark precise layouts, or position your fixture or machine components just right. All blocks include a certificate of compliance to certify their sizes are within tolerance. The certificate also lists when each block will require 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 gauge blocks are our most accurate. They help verify that precise measuring instruments, such as micrometers and calipers, are taking accurate readings. Grade AS-1 gauge blocks have a slightly higher tolerance. They’re the most common grade of gauge block.

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 for gauge blocks.

Use a gauge block holder (not included) to create a custom repeatable measurement by stacking multiple blocks together.

For technical drawings and 3-D models, click on a part number.