Measure the inside diameter of cylinders and rings. These micrometers have a plain thimble that turns freely without friction or a stopping device. It relies on user feel for accurate measurements. All include steel extensions that you can attach to one end of the micrometer head.

With an LCD screen, these micrometers make it easy to read inside diameter measurements taken from cylinders and rings. Place the micrometer inside your bore, then turn the thimble until the spindle makes contact with both sides. For an accurate reading, stop turning as soon as you feel resistance on the thimble.

USB data cables (sold separately) connect micrometers directly to your PC.

10-pin data cables (sold separately) connect micrometers to a Mitutoyo miniprocessor or multiplexer.

Wireless data transmitters and receivers (sold separately) let you send data from micrometers to your PC without a cable.

Detect variations in a range of hole diameters and depths. These sets include one dial head that fits onto three gauge bodies and 26 anvils to switch out for different holes. Use them to test engine cylinders, machine components, and other parts for issues with roundness and taper. They have a two-point contact system, which is the most common design for bore gauges. An internal pendulum balances the contact points at the true center of a hole, even if the gauge is tilted. To prevent heat from your hands skewing accuracy, all the gauges have hollow grips, which also make them easy to hold. The dial head’s highly sensitive, wear-resistant jeweled bearings contribute to a long service life, and its cover protects against scratches and drops.

Check size deviations by first setting the desired measurement with a ring gauge, bore gauge calibrator, micrometer, or caliper. The dial will display the magnitude of variation from the set measurement.

Test for size deviations across a range of hole diameters. These sets include 3 gauges and over 25 anvils marked by size for quick changes. Use them to test engine cylinders, machine components, and other parts for issues with roundness and taper. They have a two-point contact system, which is the most common design for bore gauges. For a long service life, the jeweled bearings in each dial head resist wear, and a plastic cover protects the head from scratches and drops.

Check size deviations by first setting the desired measurement with a ring gauge, bore gauge calibrator, micrometer, or caliper. The dial will display the magnitude of variation from the set measurement.

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. These gauges also detect deviations in roundness, so they can help you make sure parts don’t wear prematurely or run inefficiently. Use them for general checks when testing engine cylinders, machine components, and turbines. Designed to reach down into bores, they measure the diameter of deep holes better than calipers and inside-hole micrometers.

Once the contacts expand inside the hole, turn the screw on the handle to lock the contacts in place. To find the bore diameter, use a micrometer to measure the distance across the contacts.

A different measuring range on each gauge makes these sets handy for checking a variety of hole sizes. Each gauge has spring-loaded contacts on the probe, which expand inside holes to measure diameter. Often used for general checks, these sets can make sure that engine cylinders, machine components, and turbines don’t deviate in roundness, which could lead to wear and inefficiency if undetected. Since the gauges reach into holes farther than calipers and inside-hole micrometers, they make it easier to inspect deep holes.

Once the contacts expand inside the hole, turn the screw on the handle to lock the contacts in place. To find the bore diameter, use a micrometer to measure the distance across the contacts.

Check a variety of hole, groove, and slot diameters. Each gauge in these sets has a different measuring range. The end of these gauges has a 360° contact surface that’s easier to center in tight spaces than anvils or spring-loaded contacts. Use them to measure slots and bores in precision parts, such as electronics, where small size deviations can cause inefficiencies.

Insert the probe into a bore and turn the knob on the handle to expand the contacts. To find the bore diameter, use a micrometer to measure the distance across the contacts.

Full-ball gauges are best for deep bores. They’re less likely than half-ball gauges to tilt within the bore, which helps to avoid skewed measurements caused by placing the gauge off-center.

Half-ball gauges are best for measuring near the bottom of flat, shallow bores.

Measure the diameter of small holes, grooves, and recesses. These gauges help you find deviations in size or roundness that can cause precision parts, such as engine or valve cylinders, to wear quickly or run poorly. They have a full-ball probe, which has a 360° contact surface that’s easy to center in tight spaces. Compared to gauges with an anvil, spring-loaded contact, or half-ball probe, they’re less likely to tilt inside a bore and skew measurements.

Insert the probe into a bore and turn the knob on the handle to expand the contacts. Measure the distance across the contacts with a micrometer to find the bore diameter.

Test a variety of tight slots and holes in precision parts, such as electronics. These sets include a gauge with an LCD screen, an array of small head sizes, and setting rings. Unlike analog gauges, you don’t need a micrometer to find the diameter. Slide the full-ball probe into the hole and the diameter will show up directly on the screen, helping you detect issues with roundness. Since the probe makes 360° contact, it’s easier to center in small spots than anvils or spring-loaded contacts. It’s also less likely to tilt within a bore than a half-ball probe, which helps avoid skewed measurements. All sets come with a calibration certificate traceable to UKAS, which includes the test measurements that confirm accuracy. Choose a set with a wider measuring range to complete more measurement tasks using less tools.

The zero-set button allows you to start measuring at any point. Zero-position memory, also known as absolute (ABS) positioning, retains the gauge’s measuring position even when turned off. An SPC data output lets you connect these gauges to a computer or data processor to analyze data and monitor measurements in real time.

Use the settings rings to calibrate your gauge.

USB data cables (sold separately) connect the gauge directly to your PC.

Measure hole diameter in dirty machine shops and the outdoors with the pull of a trigger. Rated IP67, the bore gauge in these sets is protected from dust and temporary submersion in water. Sets include everything you need to measure—a pistol-grip gauge, heads of different measuring ranges, and setting rings. Thanks to its pistol grip, you can take measurements with one hand and reach into awkward angles, such as those overhead. The pistol grip also gives you precise control using just your fingertips instead of your whole hand. The LCD display directly shows the measured diameter, so you don’t need to set a baseline like you do with a dial bore gauge.

Instead of the standard two contact points, each head in these sets has three to center the probe in holes. This improves accuracy for detecting out-of-roundness, a common check for quality control. Connect the gauge to your computer, smartphone, or other device via Bluetooth or the SPC data output to monitor and analyze data in real time.

Use the included setting rings to calibrate your gauge.

Measure hole diameter and read it directly on an LCD display, no baseline measurement required. They measure deeper into smaller holes than inside hole micrometers. These Mitutoyo sets include handles with digital displays, interchangeable heads, and setting rings. Rotate the display up to 330° to see results at the angle you need. Unlike the usual two contact points, the probe has three to center the head, which means more accurate tests for out-of-roundness. To protect against bumps and corrosion, the contact points have a titanium nitride (TiN) coating. A flat-bottom anvil gives you stability to check blind holes.

An SPC data output lets you connect the gauge to a computer or data processor to monitor data and analyze trends. Zero-position memory, also known as absolute (ABS) positioning, retains the measuring position when the gauge is turned off. A zero-set button lets you start measuring at any point. For repeatable go and no-go tests, set upper and lower tolerances. A bar indicator on the display shows whether your measurement is within bounds, making test results quick to check. Alarms will sound if there are any issues, such as setting errors and low battery.

Use the included setting rings to calibrate your gauge.

10-pin data cables (sold separately) connect your gauge to a Mitutoyo miniprocessor or multiplexer.

Additional heads (not included) are available to measure other bore sizes.