Digital Three-Point Internal Micrometer Set 2-300mm – IP54, Carbide Tips & RS232/Wireless Output

Description

I. In-Depth Product Analysis

Achieving precise internal diameter measurements across a wide dimensional spectrum—from miniature 2mm bores to massive 300mm hydraulic cylinders—traditionally requires purchasing and managing multiple separate gauges. Our Digital Three-Point Internal Micrometer Set eliminates this logistical hassle by offering a complete, ready-to-use measurement system in one package. From the ultra-compact 2-6mm heads to the large 275-300mm coated models, every unit shares the same high-performance digital platform and IP54 industrial protection rating.

The core of this set's reliability lies in its three-point self-centering mechanism . As the digital thimble is rotated, three precisely calibrated measuring contacts expand outward radially at a synchronized rate. This mechanically forces the gauge to align perfectly with the absolute centerline of the bore, eliminating the off-angle readings that plague traditional two-point Calipers . For the larger measuring heads, hardened carbide measuring faces provide exceptional resistance to abrasive wear, ensuring the gauge maintains its 0.005mm to 0.007mm rated accuracy even through millions of contact cycles on cast iron and hardened steel. For critical quality assurance and SPC (Statistical Process Control) environments, the digital head features both RS232C data output (compatible with P1505 cable) and an optional wireless transmission module (P1805), allowing instant, error-free data logging directly to your computer.

II. Technical Specifications

The complete set is divided into chrome-plated smaller ranges, coated-finish mid-to-large ranges, and comprehensive kits. All measuring heads feature IP54 protection, a digital LCD, absolute/incremental measurement modes, and metric/imperial conversion.

Individual Micrometer Specifications (Coated Finish Models - 50 to 300mm):

Complete Set Specifications:

Chrome Plated Sets (Small Ranges):

Coated Finish Sets (Mid to Large Ranges):

III. FAQ (Frequently Asked Questions)

Q1: What is the main advantage of purchasing a complete 2-300mm set?
A: Purchasing a full set guarantees that every measuring head is fully calibrated and matched to its corresponding setting ring. It eliminates the risk of mixing-and-matching incompatible components from different batches, ensures you have the exact tool for every job size, and comes in a purpose-built protective case for organized storage. It offers significant cost and time savings compared to purchasing individual gauges as the needs arise.

Q2: How does the three-point self-centering system improve accuracy?
A: Standard two-point Calipers are highly susceptible to angular tilt inside a bore. The three-point system expands three contacts outward at identical rates. This forces the gauge to lock into perfect concentricity with the bore's true centerline, delivering accurate 0.005mm to 0.007mm readings for ovality, taper, and straightness without off-angle errors.

Q3: What is the purpose of the calibration (setting) rings included in the set?
A: Calibration rings are precision-ground master standards with exact internal diameters (e.g., precisely 62.000mm). Before measuring your workpieces, you insert the corresponding measuring head into its specific ring and use the SET function. This ensures that your absolute zero baseline is perfectly traceable to the master standard, guaranteeing accurate production measurements.

Q4: Why are carbide measuring faces used on the larger models?
A: Tungsten carbide is extremely hard and highly resistant to abrasive wear. When measuring cast iron, hardened tool steel, or abrasive materials, standard steel tips will slowly wear down and lose flatness over time. Carbide measuring faces ensure the gauge maintains its factory-rated accuracy for years, even under heavy industrial use. (Note: The extremely compact <12mm heads use specially hardened steel to maintain precision within tiny geometries).

Q5: How do I set up the wireless or RS232 data output?
A: The digital head features an RS232C port. You can connect the optional P1505 data cable directly to your computer. If you prefer a wireless solution, simply plug the optional P1805 wireless transmission module into the port. Both setup options allow you to instantly transfer measurement data to your SPC software, eliminating manual transcription errors and speeding up quality reporting.

IV. Applications & Industry Uses

• Precision CNC Machining & Boring: Verifying internal diameters of large milled and bored parts.

• Automotive & Engine Manufacturing: Inspecting cylinder bores, engine blocks, and transmission housings.

• Aerospace & Hydraulic Systems: Measuring deep bores, valve bodies, and structural tubing to critical tolerances.

• Mold & Die Making: Precision checking of core holes, ejector pin bores, and injection mold cavities across various sizes.

• Quality Control Laboratories: A comprehensive standard for verifying master ring gauges and large internal fixtures.

• Industrial Maintenance: Assessing internal wear of large pumps, compressors, and heavy machinery cylinders.

V. Accuracy & Working Principle (Accuracy & Mechanics)

This set achieves its reliable 0.005mm to 0.007mm accuracy through a precision mechanical wedge-and-encoder system. When the digital thimble is rotated, an internal precision screw drives three symmetrically machined wedges forward. Because the wedge angles are machined to exact tolerances, the three measuring contacts expand outward at the exact same rate, guaranteeing flawless self-centering. This mechanical displacement is converted into a digital readout by a high-resolution linear encoder. The ratchet stop mechanism guarantees a consistent measuring force across every head and every measurement, eliminating human error and ensuring repeatable results.

VI. Calibration & Maintenance

1. Daily Calibration Verification: Before a shift, select the appropriate head for the target bore. Clean the three contact points and insert the head into its dedicated calibration ring . Gently tighten using the ratchet stop, and use the SET function to confirm the zero point matches the ring's exact diameter.

2. Clean the Contacts: After every use, carefully wipe the three measuring contacts with a soft, lint-free cloth. Any grit, oil, or metal chips left on the tiny contacts will directly impact measurement accuracy.

3. Protect the Small Heads: The 2-12mm measuring heads are extremely delicate. Handle them with care. Always insert them gently into bores; do not force them, as the internal components are small and precise.

4. Annual Professional Calibration: For strict ISO 9001 or AS9100 compliance, the entire set must undergo formal, traceable calibration by a certified metrology lab every 12 months .