3-Point Internal Micrometer Holtest Set

Mitutoyo - Holtest 3-point internal micrometer set

Mitutoyo's professionally designed internal micrometer set, which is one of the most accurate and practical internal measuring tools in the Holtest series. The three-point measuring system ensures that the gauge automatically centers itself on the measurement target, and the measurement results are accurate, symmetrical, and independent of user technique. The set covers the entire 100-200mm internal diameter range with four separate micrometers, making it versatile and widely applicable to various industries.

The Holtest series is known for its ability to measure inside diameters directly, without cumbersome fitting pieces or additional calibration jigs. The series is the perfect solution for users who want a gauge that operates immediately upon unboxing, offers very high repeatability, and withstands long-term use in production environments.

Construction and technical principle of operation:

The Holtest's three-point design is based on three carbide measuring surfaces, symmetrically positioned, which open gently with the rotation of the micrometer drum. When the gauge is inserted into the hole, the surfaces naturally seek the inner wall of the hole. This automatic self-centering is one of Holtest's main advantages: the gauge does not become misaligned, and the user does not need to "turn" the tool to find the center balance. When the measuring surfaces contact the inner surface of the hole, the ratchet-stop indicates the correct measuring force with a small but clear click. This ensures that the user does not over-tighten or under-tighten the gauge—both would lead to incorrect measurement results. Thus, the measuring force remains consistent across all measurements. The advantage of the Holtest construction compared to 2-point gauges is clear: with two points, the measurement result depends on how the user supports the tool and how well the measuring surfaces align with the hole's roundness. With three points, the gauge automatically aligns with the hole geometry and measures the actual diameter of the hole, not the distance between the two points.

Contents of the set and ready for use:

List of contents:

- Number of micrometers and ranges: 100-125, 125-150, 150-175, 175-200mm
- Setting ring for each measuring range. These are very important as they enable accurate resetting of the micrometers and ensure measurement reliability.
- An extension arm for measuring deeper holes. Deep-hole measurement is often a challenge, but the Holtest design works well even when the measuring surfaces are not visible.
- A sturdy protective case that protects the measuring equipment from dents, dust, moisture, and transport damage.
- Factory verification certificate (no calibration).