Mahr

The Mahr collection spans 16 instruments across five measurement disciplines: internal diameter measurement (Micromar 44 EWR digital inside micrometer, Micromar 844 A measuring pistol, Micromar 844 EWR digital inside gage, Multimar M36B bench I.D./O.D. gages), external diameter and OD inspection (Marameter M301P series snap gage), surface roughness (Pocket Surf IV portable gage, MarSurf PS10 set), reference surface and height measurement (MarStand 107 granite surface plate and underframe), digital indicators (1086 R, 1086 R-HR, 1086 RI MarCator family), and accessory/specialty products (817 TS1 probe accessory set, MarSurf CPG contour probe arm, EGH-1028 inductive probe, D-2500 air amplifier). Mahr has been engineering precision measurement instruments for over 160 years.

The 1086 R is Mahr's flagship production digital indicator, available in three variants in this collection. The standard 1086 R combines a Reference System zero-retention mechanism which stores the established zero through power-off cycles and spindle retractions with five selectable resolutions from 0.01mm down to 0.0005mm, a 280° lockable rotating bezel, and MarConnect triple-protocol output (Digimatic, Opto RS-232C, and USB) as standard. Four measuring spans are available from 12.5mm to 100mm, in both 8mm metric and 3/8" imperial stem configurations, with approximately three-year battery life under production use. The 1086 R-HR is the high-resolution variant offering finer resolution steps reaching down to 0.0002mm for lapping, grinding, and gage calibration applications. The 1086 RI is the Integrated Wireless variant with the radio transmitter embedded directly in the housing eliminating external wireless modules for cablefree SPC data collection from production gaging stations.

The 844 A is a self-centering 3-point inside measuring pistol covering 6–200mm across 17 interchangeable head sizes. The critical difference from a conventional 2-point dial bore gauge is twofold. First, the three 44 Ak measuring head anvils are spaced at 120° intervals around the bore circumference, automatically centering the instrument on the bore axis at insertion without any rocking technique eliminating the operator skill requirement that makes handheld 2-point bore gauging reproducibility training-dependent. Second, a constant-force spring mechanism in the pistol grip applies a defined, repeatable contact force with every trigger operation regardless of how firmly the operator grips the handle, delivering cycle-to-cycle measuring force consistency that a lever-actuated gauge requires significant operator training to match. Heads from 12mm carry carbide-tipped anvils for blind-bore bottom measurement; from 40mm the heads are aluminum for weight reduction at larger diameters. A single 844 Ag basic unit accepts all 44 Ak heads within its range, and 44 Av threaded extensions add up to 150mm of additional bore depth reach. The readout indicator is selected and purchased separately.

The M301P is Mahr's indicating snap gage for rapid O.D. inspection of shafts, bolts, spindles, and stepped diameters, available in nine frame sizes covering 0–229mm (0–9"). The defining feature is its patented Channel Lock mechanism, which uses a single hex wrench to simultaneously adjust and positively lock the lower reference anvil anywhere within the 25mm (1") continuous adjustment range guaranteeing precise parallelism between the upper and lower 15.5mm × 15.5mm square tungsten carbide anvils throughout the entire sweep. Conventional snap gauges rely on multi-point clamping or friction-based retention, which allows parallelism error to accumulate when anvils are repositioned to a new nominal. The M301P maintains the same measurement integrity whether freshly set or re-ranged after a production changeover. The indicator can be rotated to read from the front or rear of the frame without tools; the 301P variant adds a lifting lever for parts with flanges or shoulders that cannot slide into the open jaw. The M301P accepts the full Mahr indicator ecosystem including Maxµm®III digital indicators with selectable resolution down to 0.5µm, and the EMD-301P and EDI-301P variants provide direct digital SPC output.

Both are Mahr surface roughness measurement instruments, but they serve different deployment scenarios. The Pocket Surf IV (models 2191802 and 2191800) is a compact, handheld, battery-powered roughness gage with a large digital LCD and single-button operation purpose-designed for fast, in-process surface finish checks directly on the production floor or at the machine without setup overhead. It is the right tool when an operator needs an immediate pass/fail roughness check on a freshly machined or ground part. The MarSurf PS10 Set (6910232) is a higher-capability portable surface roughness tester system bundled with a 5µm probe, designed for more comprehensive surface texture measurement across a wider range of parameters and applications including reporting and documentation. The PS10 is better suited for quality lab, incoming inspection, and applications where detailed measurement data and documentation are required in addition to on-the-spot evaluation.

The Mahr MarStand 107 G is Mahr's precision granite surface plate which is a reference datum foundation engineered to the flatness and stability requirements of high-accuracy comparative measurement, height gauging, and surface plate inspection work. Granite is the preferred material for precision surface plates because its dimensional stability, vibration damping, non-magnetic properties, and freedom from residual stresses produce a reference surface that maintains its flatness specification over decades of use in controlled environments. The Mahr 107 MarStand Underframe is the purpose-designed cabinet and stand system for the 107 G plate, providing the rigid, vibration-resistant support structure needed to maintain surface plate flatness in a production metrology environment. Together they form the complete MarStand 107 system which is an integrated reference station for indicators, height gauges, comparators, and bench gages that require a stable, flat reference surface to deliver their specified accuracy.

Both are digital inside measuring instruments with integrated digital readout for internal diameter measurement, but they are designed for different geometries and application types. The Micromar 44 EWR is a digital inside micrometer, a 2-point contact instrument using the traditional micrometer spindle-and-thimble mechanism with digital readout, suited for through-hole and blind-bore measurement where the operator positions and reads a direct absolute inside diameter. The Micromar 844 EWR is the fully digital version of the 844 measuring pistol platform, a 3-point self-centering inside measuring gage with integrated digital display for direct readout without a separate indicator, covering 6–200mm. The 844 EWR delivers the self-centering speed and operator-independence of the 3-point system with the convenience of a built-in digital readout, making it the natural evolution of the 844 A for production lines where cable-free SPC or wireless output integration is the primary requirement.

The Multimar M36B-10 and M36B-20 are 2-point "T"-plate bench indicator gages designed for fast, accurate comparative I.D. and O.D. measurement in a fixed bench station rather than handheld. A bench gage removes operator position variability entirely, the part is presented to the gage in a controlled, repeatable orientation, and the instrument reads the dimension without any influence from how the operator holds or angles the tool. This makes bench gages the preferred solution for high-volume production inspection stations, where the same feature is measured hundreds or thousands of times per shift to tight tolerances and cycle time, repeatability, and gage R&R performance are all critical. The M36B is particularly well-suited for shaft O.D. and bore I.D. inspection in automotive, bearing, and precision machining environments where measurement data feeds directly into SPC systems.

The Mahr D-2500 Air Amplifier (2095184) is a high-performance pneumatic measurement component that amplifies compressed air flow for use in air gaging applications. With a 2500:1 amplification ratio, 0.00005" resolution, and a ±0.0015" measuring range on an analog display, it is the readout and signal processing unit in an air gauging circuit. The instrument that converts the small pressure differential produced by an air tooling plug or ring into a readable dimensional deviation. Air gaging is widely used in high-volume production inspection of bores, shafts, and cylindrical features where contact gauging is too slow or would mark the surface, where the measurement must be made in the presence of coolant or cutting fluid, or where the bore geometry is too small for a dial bore gage to enter. The D-2500 represents Mahr's pneumatic measurement heritage and integrates with dedicated Mahr air tooling for complete air gaging system configurations.

All Mahr orders ship free to the continental USA, backed by a best-price guarantee. A 30-day return policy and Affirm financing at checkout are available for all products. Government and institutional buyers can submit an RFQ through the dedicated Government RFQ page (DUNS: 13-715-2209, CAGE: 15F67). Mahr instruments involve detailed configuration decisions like indicator shank size and resolution variant, measuring span selection, head-only vs. complete set, with or without lifting lever, and stem vs. integrated wireless and getting the specification wrong means an instrument that won't fit the gage body or won't connect to the data collection system. Gustavo personally reviews every order and strongly encourages buyers to call or text 617-398-7852 before purchasing, Monday through Friday, 8am–5pm EST.