Mitutoyo 103-138 : Outside Micrometer Range 25-50mm
The Mitutoyo 103-138 is a precision outside micrometer covering the 25–50 mm measurement range with 0.01 mm graduation, manufactured by Mitutoyo — the world's leading maker of dimensional measuring instruments. Part of Mitutoyo's trusted 103 series, this micrometer is the go-to instrument for checking shaft diameters, turned features, and machined components that fall in the 25–50 mm range across machine shops, quality labs, and production floors in the UAE.
Built to ISO 3611 and DIN 863 standards, the 103-138 delivers ±2 µm accuracy with carbide-tipped, micro-lapped measuring faces for long-term wear resistance and reliable full-face contact. It ships with a 25 mm setting standard for zero-point calibration — essential for maintaining measurement integrity shift after shift.
✦ Key Features
Carbide-Tipped Measuring Faces — Micro-lapped to 0.6 µm flatness. Withstands repeated contact with hardened steel, aluminium, and stainless steel without losing accuracy.
25 mm Setting Standard Included — Allows precise zero-point calibration before every measurement session, ensuring traceable accuracy from day one.
Ratchet Thimble — Applies consistent 5–10 N measuring force on every reading, eliminating operator-dependent variation.
Spindle Lock — Clamp the spindle at any position for comparative measurements or gauge setting without losing the reading.
Satin Chrome Finish — Anti-glare barrel and thimble for easy reading under shop-floor fluorescent and LED lighting.
Heat-Insulating Plates — Minimise thermal expansion from hand contact during extended measurement sessions.
📐 Technical Specifications
| Model | 103-138 |
| Range | 25–50 mm |
| Graduation | 0.01 mm |
| Accuracy (MPE) | ±2 µm |
| Flatness | 0.6 µm |
| Parallelism | 2 µm |
| Measuring Faces | Carbide-tipped, micro-lap finish |
| Spindle Diameter | ø6.35 mm (≤300 mm) / ø8 mm (>300 mm) |
| Spindle Pitch | 0.5 mm |
| Thimble Type | Ratchet |
| Measuring Force | 5–10 N |
| Scale | Satin chrome, ø18 mm |
| Mass | ~215 g |
| Standard | ISO 3611 / DIN 863 |
| Delivered With | Box, 25 mm setting standard, spanner key, inspection certificate |
| Origin | Mitutoyo (Japan) |
🏭 Applications
CNC Turning & Milling — Verify shaft diameters, step lengths, and bore features in the 25–50 mm range between machining operations.
Quality Control & Incoming Inspection — Check received components against drawing tolerances before assembly or further processing.
Tool and Die Making — Measure punch diameters, die bores, and precision-ground surfaces within the 25–50 mm range.
Maintenance and MRO — Check bearing journals, coupling diameters, and piston dimensions during overhaul and scheduled maintenance.
Calibration Labs — A reliable working standard for comparative measurement and gauge verification.
Why Buy from San Tools?
✅ Authorised Mitutoyo Distributor — Genuine product with full manufacturer warranty.
✅ In Stock in Dubai — Ships same-day from our Al Quoz warehouse.
✅ Calibration Certificates — Traceable certificates for ISO 9001 and IATF 16949 audits.
✅ Free UAE Delivery — On orders over AED 500.
✅ Expert Support — 38 years matching the right instrument to the right application.
Frequently Asked Questions
Is this a genuine Mitutoyo product?
Yes. San Tools is an authorised Mitutoyo distributor in the UAE. Every micrometer ships with Mitutoyo packaging and an inspection certificate.
Does the 103-138 come with a setting standard?
Yes. All Mitutoyo micrometers from 25 mm upward include a setting standard for zero-point calibration. The 103-138 ships with a 25 mm setting standard in the box.
Can I get a calibration certificate?
Yes. We provide traceable calibration certificates on request — essential for ISO 9001, IATF 16949, and AS 9100 quality systems.
What is the difference between the 103-138 and the 103-137?
The 103-137 covers 0–25 mm and zeroes against its own anvil. The 103-138 covers 25–50 mm and includes a 25 mm setting standard for calibration. Accuracy and build quality are identical across the 103 series.