Micrometers

The collection spans four trusted brands (Insize, Mitutoyo, Starrett, and Mahr) across seven distinct micrometer types: outside micrometers (sets and individual), outside micrometers with extension anvil collars, digital two-point and three-point internal micrometers, wide-range three-point internal micrometers, tubular inside micrometers, digital tubular inside micrometers, blade-type micrometers, and laser scan micrometers. This breadth makes the collection a single source for virtually every micrometer requirement from a standard bench outside micrometer set to a laser scan system measuring down to 1µm without contact. All products ship from an authorized dealer with 100% authentic instruments.

An outside micrometer measures the external dimensions of a part such as shaft diameters, material thickness, flange widths by closing its anvil and spindle against the outside surfaces. An inside micrometer measures internal dimensions such as bore diameters, slot widths, hole-to-hole distances by expanding its contacts to bear against the internal surfaces. A tubular inside micrometer extends that concept to large bores using a modular rod-and-extension system: a micrometer head attaches to a series of interchangeable tubular extension rods, adding exactly one rod's length per step to span bores that a standard inside micrometer cannot reach. Insize tubular inside micrometers in this collection cover internal diameters from 2" up to 60" (digital versions from 6" up to 60"), making them the right tool for large pipes, pressure vessel bores, and heavy equipment cylinders.

A three-point internal micrometer uses three carbide-tipped contacts spaced 120° apart that simultaneously expand against the bore wall, self-centering automatically on the bore axis. This eliminates the rocking technique required to find the true diameter with two-point instruments and significantly reduces the operator skill requirement for accurate, repeatable bore measurement. Insize offers both digital two-point models (3127-E Series, IP65, 0.00005"/0.001mm resolution) and digital three-point models (3127-E12, 3127-E24, IP65, 0.00005"/0.001mm), plus wide-range three-point models (3128-12, IP54, 0.0001"/0.001mm resolution with extension rods and setting rings) and the 3228-10 mechanical three-point (0.0001" graduation with 6" diameter setting ring). Three-point micrometers are the preferred choice for production bore inspection where speed, consistency, and gage R&R performance are critical.

The Insize 3661 Series addresses the primary source of repeatability error in conventional outside micrometers: spindle rotation. In a standard micrometer, the spindle rotates as the thimble turns and the contact point therefore exerts a slight rotational torque on the part surface at the moment of contact, which can cause the part to shift or introduce frictional force variation that affects the reading, particularly on small cylindrical or delicate parts. The 3661's non-rotating spindle eliminates this by decoupling the spindle's rotational movement from its linear advancement which is the measuring face contacts the part without any rotational torque. The result is resolution selectable among 0.0005mm, 0.00002", and 0.00005", repeatability of 0.5µm, measuring face flatness of 0.3µm, and parallelism of 0.5µm which are specifications that place these instruments firmly in the calibration lab and ultra-precision production inspection category.

The Insize LDM-D090 is a non-contact laser scan micrometer covering 0.5–90mm with 1µm resolution. Rather than contacting the part surface with anvil and spindle, it scans the part's shadow across a collimated laser beam and calculates the diameter from the interruption pattern and all without any mechanical contact. This solves several problems that contact micrometers cannot address: measuring soft, delicate, or freshly coated surfaces without deformation or marking; measuring parts moving on a production line at speed without stopping the process; measuring very small wire diameters, fibers, or features where a micrometer's contact force would distort the measurement; and achieving sub-micron precision on features where measuring force variability would introduce unacceptable uncertainty. The LDM-D090 bridges the gap between hand micrometers and full CMM-based inspection for applications demanding both high throughput and high precision.

The Insize 3205 Series is an outside micrometer fitted with adjustable extension anvil collars that allow a single micrometer head to cover multiple measurement ranges by repositioning the collar to different preset locations rather than requiring a separate micrometer for each 1" measurement range. Models in the series include the 3205-48, 3205-56, 3205-64, 3205-72, and 3205-80, covering ranges up to 80mm. The 0.0005" graduation and carbide measuring faces deliver the same accuracy as a standard outside micrometer while reducing the number of instruments needed for multi-range measurement programs. This is particularly valuable in heavy machining environments where large-diameter shafts, flanges, or bearings must be measured across a wide span of diameters without maintaining a full set of individual micrometers.

A blade-type micrometer replaces the standard flat anvil and spindle with narrow, precision-ground blade-shaped contacts (typically just 1–2mm wide) that can reach into narrow slots, ring grooves, keyways, recesses, and undercuts where a standard micrometer's flat anvil and spindle face cannot fit. The Starrett 486P-10 covers the 9"–10" range with carbide-tipped blades, a friction thimble for controlled measuring pressure, and a satin-chrome frame for durability and glare-free readability. It is the standard tool for measuring the width of turned ring grooves on shafts and pistons, the depth of keyway recesses in precision bores, and external features in tight geometries where only a blade-shaped contact can access the measurement surface. A spanner wrench and case are included.

The collection carries three outside micrometer sets serving different unit system and range requirements. The Starrett ST436.1CXRLZ covers 0–6" in inch graduation with carbide-tipped measuring faces, satin-chrome thimble, ratchet stop, and locknut which is the standard workhorse configuration for inch-system machine shops. The Starrett S436MEXRLZ covers 0–150mm in 25mm steps for metric-system environments, with identical construction quality. The Mitutoyo 103 Series Inch Outside Micrometer Set provides Mitutoyo's precision and brand legacy in an inch-system set. The Mitutoyo and Starrett sets both include individual fitted cases and setting standards for field calibration of each micrometer. The Insize 3203-1212A set extends coverage to the full 0–12" range across twelve individual micrometers in a single fitted hard case making it the most comprehensive bench solution in the collection for shops that routinely measure across a wide span of part sizes.

Several digital micrometers in this collection offer direct wired data output for SPC integration. The Insize digital internal micrometers (3127-E Series, 3128 Series) include data output buttons and are compatible with INSIZE SPC data collection systems via standard Mitutoyo Digimatic-compatible protocol. The Mahr Micromar 40 EWR digital inside micrometer (available in this collection via the Mahr section) features MarConnect triple-protocol output (Digimatic, RS-232C, USB) as standard. The Insize 3661 non-rotating spindle micrometers include data output compatible with standard SPC platforms. Wireless-capable variants of the Mahr platform (the 40 EWRi series) embed the radio transmitter directly in the instrument for cablefree SPC data collection. For regulated quality systems requiring paperless inspection documentation, confirming the specific output protocol of the model you are purchasing before ordering is recommended.

All micrometer orders ship free to the continental USA and are backed by a best-price guarantee. A 30-day return policy and Affirm financing at checkout are available. Government agencies, calibration labs, and defense contractors can submit an RFQ through the dedicated Government RFQ page (DUNS: 13-715-2209, CAGE: 15F67). Micrometer selection involves multiple interacting decisions such as type, range, graduation, spindle configuration, IP rating, data output protocol, and whether a set or individual instrument best fits the application. Gustavo personally reviews every order and is available to help buyers identify the right specification before they commit simply call or text 617-398-7852, Monday through Friday, 8am–5pm EST.