Find precise convex and concave radii of tools, patterns, and dies.

Check step height, gap width, and the distance between narrow slots to make sure machine and engine parts seamlessly align. These highly precise gauges access spots where calipers and other measuring tools can’t fit. They’re often used to test the height of rivets and other fasteners to ensure loads are distributed evenly. Made of stainless steel, the gauge body and blade resist corrosion.

You’ll need to calibrate the gauge before each use for accurate readings. Press both jaws into the included zero-setting block to zero the gauge. Before measuring internal gaps and narrow slots, you’ll also need to set a baseline with a micrometer (not included). Line up the gauge’s jaws with the micrometer’s face.

These gauges have a power button, but you can also wake them up just by picking them up. Don’t worry about this draining the battery—the gauge turns off after five minutes of inactivity.

Whether a chamfered edge is in a screw hole or on the end of a rotary shaft, these gauges find its diameter. Use them to confirm the tolerance of edges after milling, drilling, and reaming. They measure chamfers on the inside or outside diameter of your bore. As you trace the probe of these gauges along an edge, an internal sensor records the distance and angle. The calculated diameter displays on the LCD screen for quick readings. All have SPC data output to transfer information to your computer or data processor—you don’t even need any cables.

Choose a gauge with an angle that is greater than or equal to the chamfer angle you are trying to measure.

To measure thickness in areas where standard feeler gauges don’t fit, these sets have leaves with narrow ends. They're used to check gaps, alignment, and narrow slots. Sets include leaves in a variety of thicknesses that are riveted together in a fan design that folds up for portability. Each leaf is marked with thickness. Leaf-securing locks hold individual gauge leaves in place.

A certificate of calibration traceable to NIST states that these sets have passed a test for accuracy. They’re used to check small gaps, narrow slots, and alignment. The leaves have a narrow end to measure thickness in areas where standard feeler gauges don’t fit. For example, they can measure gaps when setting engine components such as spark plugs to make sure there’s enough space so friction doesn’t lead to inefficiency.

Sets include leaves in a variety of thicknesses that are riveted together in a fan design that folds up for portability. Each leaf is marked with thickness. Leaf-securing locks hold individual gauge leaves in place.