Mitutoyo 293-355-30 Digimatic IP65 Micrometer

Technical Overview

IP65-rated digital micrometer with 9-10" (228.6-254mm) range, 0.0001" resolution, ±0.0002" accuracy, ratchet stop constant force, and SPC data output.

Key Features

IP65 protection level allows usage in environments exposed to cutting oil, coolants, dust, and water splashes.
Ergonomic anti-slip frame cover and front panel design ensure stable handheld measurements.
Ratchet stop mechanism provides constant measuring force (5-10 N) for high repeatability.
Equipped with SPC Digimatic data output port to enable integration with quality control systems.
Features origin-set, zero-setting, data hold, auto power on/off, and inch/mm conversion.
Carbide-tipped measuring faces with a micro-lap finish preserve flat and parallel accuracy.
Long battery life of approximately 1.2 years under normal usage with a single SR44 battery.

Technical Specification Matrix

Parameter	Value
Measuring Range	9 - 10 in (228.6 - 254 mm)
Resolution	0.0001 in (0.001 mm)
Accuracy	±0.0002 in (±4 µm)
IP Rating	IP65
Parallelism	0.00016 in (4 µm)
Flatness	0.000012 in (0.3 µm)
Measuring Force	5 to 10 N
Data Output	Yes (Digimatic SPC)
Battery Type	SR44 (1 pc.)
Battery Life	Approx. 1.2 years
Measuring Spindle Diameter	6.35 mm
Spindle Pitch	0.635 mm (0.025 in)
Constant-Force Device	Ratchet Stop
Physical Weight (kg)	1.27
Dimensions L x W x H (cm)	42.1 x 18 x 3

Industrial Applications

1. Precision Automotive Crankshaft Inspection

Used in automotive manufacturing plants to measure the main journal diameters of large diesel engine crankshafts (typically in the 9 to 10 inch range) directly in the machining area to maintain bearing clearances.

Problem Solved

Standard digital electronics easily fail due to splashing cutting fluids and ambient metal dust. The IP65 rating protects the device from sensor errors caused by coolant, while the ±0.0002" accuracy limits ensure the journals meet strict dimensional requirements.

Crankshaft InspectionIP65 WaterproofBearing ClearancePrecision Metrology

2. Aerospace Transmission Shaft Turning Quality Control

Applied on the aerospace machine shop floor to inspect large-diameter turbine or rotor transmission shafts during final machining passes.

Problem Solved

Thermal expansion from operator contact introduces dimensional error during long inspection cycles. The micrometer's heat-shielded frame eliminates expansion errors, while the SPC output allows operators to directly export values to SPC databases to ensure AS9100 regulatory logging compliance.

Aerospace Shaft TurningSPC Data OutputThermal Expansion ShieldAS9100 Quality Control

3. Heavy-Duty Hydraulic Cylinder Piston Rod Verification

Used to gauge the outer diameter of newly turned and polished heavy-duty hydraulic cylinder piston rods to verify dimensions prior to chrome plating.

Problem Solved

Large hand-held micrometers suffer from human-induced measurement variability. The integrated ratchet stop guarantees a constant measuring force of 5-10 N, removing user tactile bias, while carbide-tipped faces prevent premature wear from highly abrasive chrome and steel surfaces.

Hydraulic CylindersConstant Force RatchetCarbide-Tipped FacesO.D. Measurement