Measure the inside diameter of holes and cylindrical bores, as well as identify out-of-roundness problems.

The dial on these gauges displays size deviations in real time. These gauges measure small slots and bores in precision parts, such as electronics, where even small size deviations can cause inefficiencies.

Check a hole’s diameter and detect out-of-roundness problems.

Test for size deviations across a range of hole diameters.

Measure a variety of hole diameters. These sets include gauges that use spring tension to expand the probe’s contacts inside of bores.

Inspect a variety of hole sizes with the gauges in these sets. Each has spring-loaded contacts on the probe, which expand inside holes to measure diameter.

Position these gauges snugly within your bore to measure its diameter. Spring tension pushes the gauge’s two telescoping steel contacts against the walls of your bore.

Measure the diameter of small holes, grooves, and recesses.

With an LCD screen, these micrometers make it easy to read inside diameter measurements taken from cylinders and rings.

Reach into bores to measure the precise size and location of grooves.

Measure bore diameter directly. These gauges give you the actual diameter, unlike a dial bore gauge, which only shows the variation from a set measurement.

Check the diameter of holes with the pull of a trigger. These Starrett sets have everything you need for one-handed measurements—a pistol-grip gauge, heads for varying diameters, and setting rings.

Make sure the top diameter of a chamfered hole isn’t too big or too small.

Use these Class Z go gauges to check the minimum hole diameter. Also known as pin gauges, they help you measure hole size and depth, check hole location and distance, and set micrometers.

These Class Z no-go gauges help you check the maximum hole diameter. Commonly known as pin gauges, use them to measure hole size and depth, check hole location and distance, and set micrometers.

A black-oxide treatment on these go gauges shows wear patterns so you can tell when you need to calibrate or replace the gauge—use them to check to minimum hole diameter.

Take precision go/no-go measurements of hole sizes and depths, check hole location and distance, and set micrometers.

Get your choice of one target-size gauge with 12 larger gauges and 12 smaller gauges, graduated in 0.0001”. Use these sets to measure hole sizes and depths, check hole locations and distance, and set micrometers.

Check the true diameter of holes, even if they’re bent or curved. The thin stem on these gauges flexes to reach features deep inside holes and cavities.

A certificate of calibration traceable to NIST states that these sets have passed a test for accuracy.

Check slot widths and hole diameters with the markings on these gauges. Leaves in a variety of sizes are riveted together in a fan design—spread them out for use or fold them in for portability.

Check a range of thicknesses with a single tapered gauge.

Replace an entire feeler gauge set with one of these tapered gauges that lets you check a range of thicknesses.

A notch on the handle indicates when the internal NPT threads you’re checking are in tolerance.

Ensure the accuracy of NPT thread measurements—these gauges come with a certificate of calibration traceable to NIST that states they’ve passed a test for accuracy.

Use the Mitutoyo gauge blocks in these sets individually or together to take precise measurements or calibrate your measuring tools. All come with a certificate traceable to NIST to certify they were calibrated in a lab and meet tight tolerances.

Use the Starrett gauge blocks in these sets individually or together to take precise measurements or calibrate your measuring tools. All have been laboratory calibrated and include NIST traceable certification with the tested measurements.

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.