Mitutoyo 345-351-30 Digimatic Caliper-Type Inside Micrometer, 1-2 in - Anvil Jaw, 0.00005 in / 0.001mm Resolution

The Mitutoyo 345-351-30 is a caliper-type inside micrometer from Series 345, built for direct measurement of internal diameters, groove widths and other inside dimensions from 1-2 in. Unlike a tubular inside micrometer, the caliper jaws reach into features that a straight rod cannot, and this model is fitted with anvil jaws to suit bores, bosses, slots and other internal diameters across its range.

Both measuring faces are carbide tipped, so they hold their geometry through heavy shop-floor use. A constant measuring-force device applies the same force on every reading, which is what keeps results repeatable between operators rather than depending on feel. A locking clamp holds the spindle so the micrometer can be withdrawn from the bore and read without the setting shifting, and the satin-chrome finish on the thimble and sleeve cuts glare under shop lighting.

The Digimatic LCD reads to 0.00005 in / 0.001 mm and the instrument is accurate to +/-0.0003 in across its range. SPC data output connects it to a Mitutoyo IT or DP unit, the USB Input Tool Direct or a U-WAVE wireless transmitter for MeasurLink and other data-collection systems. Power comes from a single SR44 battery, good for roughly 2.4 years in normal use.

Key features

• Measuring range: 1-2 in
• Resolution: 0.00005 in / 0.001 mm
• Accuracy: +/-0.0003 in
• Anvil jaws, carbide-tipped measuring faces
• Zero/ABS setting and two presets
• Data hold, function lock and low-voltage alarm
• Auto power off after 20 minutes of non-use
• SPC data output
• Spindle lock clamp and constant measuring-force device

Supplied in a fitted case with a spanner and battery. A setting standard is required to set the micrometer to its reference point and is not supplied; setting rings, the CERA Inside Micro Checker and gauge block accessory sets are available separately. A cap and holder are needed to mount the instrument on a micrometer stand.