Original price was: $ 476.56.$ 409.17Current price is: $ 409.17.
Mitutoyo 331-261-30 Digital Spline Micrometer IP65 – precision tool for measuring splined shafts, slots & keyways. Features IP65 coolant protection, 0-25mm range, and ±2µm accuracy.
The Mitutoyo 331-261-30 Digital Spline Micrometer IP65 is a high-precision measuring instrument designed for grooves, splined shafts, slots, and keyways. With its small-diameter anvil and spindle, it ensures accurate measurements in tight spaces where standard micrometers cannot reach. Engineered with IP65 protection, it offers excellent resistance against water and dust, making it ideal for workshop and machining environments exposed to coolant splashes. This tool combines durability with advanced digital functionality for reliable performance in demanding conditions
The Mitutoyo 331-261-30 provides a 0–25 mm measuring range with a 0.001 mm digital step and ±2 µm maximum permissible error, ensuring exceptional accuracy. Its carbide-tipped, micro-lapped measuring faces deliver long-term wear resistance, while the large 7.5 mm LCD display ensures easy reading. Powered by a long-lasting SR44 battery (approx. 2.4 years), it includes features such as origin setting, ABS/INC switching, hold function, and auto power-off. With a measuring force of 5–10 N, lightweight 330 g body, and coolant-proof IP65 design, it is built for precision, reliability, and convenience
Because it redefines precision for specialized measurements. Unlike conventional micrometers, this model is tailored for spline, slot, and keyway inspection, where accuracy in restricted geometries is critical. Its stepped, carbide-tipped spindle allows access to hard-to-reach features, while the IP65 protection ensures it can withstand tough shop-floor environments. Backed by Mitutoyo’s legacy of metrology excellence, this instrument combines innovation, durability, and user-friendly operation, making it the perfect choice for professionals who demand uncompromising accuracy.
Traditional micrometers struggle with grooves, splines, and narrow slots, often leading to inaccurate readings or the need for multiple tools. The Mitutoyo 331-261-30 solves this by offering a compact anvil and spindle design specifically engineered for these challenging geometries. With its digital precision, dust and coolant resistance, and versatile measuring functions, it eliminates guesswork and minimizes downtime in machining processes. This means users gain higher measurement confidence, reduced errors, and improved workflow efficiency in industries where quality control is critical.
Production teams measure tooth land thickness on splined shafts at specific depths to validate broaching quality and gear fit. The micrometer’s small-diameter, stepped anvil/spindle reaches between teeth without fouling fillets, while the 0.001 mm resolution and ±2 µm MPE support tight tolerance calls. IP65 protection lets inspectors measure right at the machine, even with coolant present, reducing transport time and rework loops.
After keyway machining, technicians confirm slot width and consistency along the length to prevent loose keys or press-fit damage. The 2 mm tip geometry accesses narrow slots, enabling repeatable readings at multiple depths to detect taper or tool wear. Digital step size and HOLD/ABS-INC functions simplify comparisons to nominal and save intermediate checkpoints, even on oily parts thanks to the IP65 housing.
In high-mix precision assembly (e.g., metrology fixtures, electronic connectors), slot width uniformity is critical for alignment and clamping forces. The carbide-tipped, micro-lapped faces minimize wear, sustaining accuracy across frequent checks, while the 7.5 mm LCD aids quick readouts on crowded benches. Sampling at entry, mid-depth, and base reveals drift from cutter deflection, guiding corrective offsets before a full batch is affected.
Valve spools, piston ring grooves, and sealing grooves demand controlled widths to preserve pressure integrity and reduce leakage. With a measured force of 5–10 N and a robust, coolant-proof build, the tool delivers consistent readings on lubricated components straight from the line. Data output compatibility supports traceability—operators can log results for SPC, flagging deviations early to avoid downstream tear-downs or warranty returns.
| Feature | Details | Benefit |
|---|---|---|
| Model | 331-261-30 (SPM2-25MX) | Identifies the exact Mitutoyo spline micrometer model for traceability and purchase accuracy. |
| Measuring Range | 0 – 25 mm | Covers the most common spline, slot, and keyway measurement needs in precision machining. |
| Resolution (Digital Step) | 0.001 mm | Ensures extremely fine readings for tight tolerance control. |
| Maximum Permissible Error (MPE) | ±2 µm | Provides reliable accuracy for critical applications such as spline shafts and grooves. |
| Flatness | 0.3 µm | Guarantees consistent contact for high-precision surface measurements. |
| Parallelism | 2 µm | Maintains accuracy when measuring across splines or narrow features. |
| Display | Large LCD, 7.5 mm character height | Easy-to-read values reduce operator error in busy workshop environments. |
| Anvil & Spindle Design | Stepped, small-diameter carbide-tipped | Enables access into narrow grooves, slots, and splines where standard micrometers cannot measure. |
| Protection Level | IP65 (coolant & dust resistant) | Suitable for use directly in machining areas with coolant splash or dust exposure. |
| Measuring Force | 5 – 10 N | Provides stable and repeatable readings without deforming delicate parts. |
| Spindle Lock | Equipped with ø6.35 mm spindle, pitch 0.5 mm | Allows precise positioning and reliable repeat measurements. |
| Functions | ORIGIN, ABS/INC, HOLD, Auto Power OFF, Low Voltage Alarm, Function Lock | Improves usability, prevents errors, and supports different measurement tasks. |
| Power Supply | 1 × SR44 battery | Standard, widely available battery with approx. 2.4 years life for reduced downtime. |
| Body Weight | Approx. 330 g | Lightweight yet robust for both bench and shop-floor use. |
| Material & Finish | Carbide-tipped measuring faces, satin chrome sleeve & thimble | Long-lasting wear resistance and smooth handling for daily use. |
| Data Output | Compatible with Digimatic & U-WAVE wireless systems | Enables digital data transfer and integration into SPC/quality control workflows. |
| Optional Accessories | Micrometer stands, Digimatic cables, U-WAVE Bluetooth transmitters | Expands versatility for automated measurement logging and hands-free inspection setups. |
| L: |
58,2 mm
|
| a: |
17,5 mm
|
| b: |
7,3 mm
|
| c: |
32,5 mm
|
All products of product family Series 331:
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Digital Spline Micrometer IP65 |
| 0-25mm, 2mm Measuring Face | |
| Mitutoyo Part Number: 331-261-30 | |
| More Info | |
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Digital Spline Micrometer IP65 |
| 0-25mm, 3mm Measuring Face | |
| Mitutoyo Part Number: 331-251-30 | |
| For more : Contact us | |
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Digital Spline Micrometer IP65 |
| 25-50mm, 3mm Measuring Face | |
| Mitutoyo Part Number: 331-252-30 | |
| For more : Contact us | |
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Digital Spline Micrometer IP65 |
| 25-50mm, 2mm Measuring Face | |
| Mitutoyo Part Number: 331-262-30 | |
| For more : Contact us | |
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Digital Spline Micrometer IP65 |
| 50-75mm, 3mm Measuring Face | |
| Mitutoyo Part Number: 331-253-30 | |
| For more : Contact us | |
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Digital Spline Micrometer IP65 |
| 50-75mm, 2mm Measuring Face | |
| Mitutoyo Part Number: 331-263-30 | |
| For more : Contact us | |
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Digital Spline Micrometer IP65 |
| 75-100mm, 3mm Measuring Face | |
| Mitutoyo Part Number: 331-254-30 | |
| For more : Contact us | |
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Digital Spline Micrometer IP65 |
| 75-100mm, 2mm Measuring Face | |
| Mitutoyo Part Number: 331-264-30 | |
| For more : Contact us | |
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Digital Spline Micrometer IP65 |
| Inch/Metric, 0-1″, 3mm Measuring Face | |
| Mitutoyo Part Number: 331-351-30 | |
| For more : Contact us | |
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Digital Spline Micrometer IP65 |
| Inch/Metric, 0-1″, 2mm Measuring Face | |
| Mitutoyo Part Number: 331-361-30 | |
| For more : Contact us | |
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Digital Spline Micrometer IP65 |
| Inch/Metric, 1-2″, 3mm Measuring Face | |
| Mitutoyo Part Number: 331-352-30 | |
| For more : Contact us | |
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Digital Spline Micrometer IP65 |
| Inch/Metric, 1-2″, 2mm Measuring Face | |
| Mitutoyo Part Number: 331-362-30 | |
| For more : Contact us | |
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Digital Spline Micrometer IP65 |
| Inch/Metric, 2-3″, 3mm Measuring Face | |
| Mitutoyo Part Number: 331-353-30 | |
| For more : Contact us | |
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Digital Spline Micrometer IP65 |
| Inch/Metric, 2-3″, 2mm Measuring Face | |
| Mitutoyo Part Number: 331-363-30 | |
| For more : Contact us | |
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Digital Spline Micrometer IP65 |
| Inch/Metric, 3-4″, 3mm Measuring Face | |
| Mitutoyo Part Number: 331-354-30 | |
| For more : Contact us | |
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Digital Spline Micrometer IP65 |
| Inch/Metric, 3-4″, 2mm Measuring Face | |
| Mitutoyo Part Number: 331-364-30 | |
| For more : Contact us |
Optional accessories:
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Micrometer Stand, 45° Angle Type |
| for Micrometer 0-50mm/0-2″ | |
| Mitutoyo Part Number: 156-105-10 | |
| For more : Contact us | |
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Micrometer Stand, Adjustable Angle Type |
| for Micrometer 0-100mm/0-4″ | |
| Mitutoyo Part Number: 156-101-10 | |
| More Info | |
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Connection Unit for IP Caliper, Micrometer |
| with Data Button for U-WAVE fit, U-WAVE fit Bluetooth | |
| Mitutoyo Part Number: 02AZF310 | |
| For more : Contact us | |
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USB Input Tool Direct (Digimatic to USB) |
| 2m Cable, Digimatic/Digimatic 2, with Data Button IP Micrometer Type | |
| Mitutoyo Part Number: 06AFM380B | |
| More Info | |
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Digimatic Cable with Data Button IP Type |
| 1m, Micrometer Type | |
| Mitutoyo Part Number: 05CZA662 | |
| More Info | |
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Digimatic Cable with Data Button IP Type |
| 2m, Micrometer Type | |
| Mitutoyo Part Number: 05CZA663 | |
| For more : Contact us | |
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U-WAVE fit, IP67 Type |
| Wireless Transmitter for Micrometer/Indicator | |
| Mitutoyo Part Number: 264-622 | |
| For more : Contact us | |
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U-WAVE fit, Buzzer Type |
| Wireless Transmitter for Micrometer/Indicator | |
| Mitutoyo Part Number: 264-623 | |
| For more : Contact us | |
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U-WAVE fit Bluetooth, IP67 Type |
| Wireless Transmitter for Micrometer/Indicator | |
| Mitutoyo Part Number: 264-626 | |
| For more : Contact us | |
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U-WAVE fit Bluetooth, Buzzer Type |
| Wireless Transmitter for Micrometer/Indicator | |
| Mitutoyo Part Number: 264-627 | |
| For more : Contact us |
Consumable spares:
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Battery SR44 1.5V |
| 938882 | |
| For more : Contact us |
For expert guidance before placing your order.
Warranty – 1-year warranty for your peace of mind.
Global Shipping – We ship worldwide with secure packaging and reliable delivery.
Technical Support – Contact us for professional after-sales technical assistance.
