Mitutoyo 526-156 Extra Small Hole Bore Gauge, Range .145 - .29", Graduation .0001"
Part No. 526-156 | Range 0.145"–0.29" (3.683–7.366 mm) | Graduation 0.0001"
General Tech Services LLC — Genuine Mitutoyo Distributor, Kuwait +965 9807 4888
Product Overview
The Mitutoyo 526-156 extra small hole bore gauge measures very small internal diameters from 0.145"–0.29" (3.683–7.366 mm) with a split two-point contact and 0.0001" analogue indicator. Unlike pin gauges that provide mainly pass/fail information, this bore gauge provides a measured size for more detailed inspection and process control.
The contact point has a hard chrome finish for durability. The supplied analogue indicator can be replaced with a customer-supplied Digimatic indicator when digital measurement is required. The Mitutoyo 526 series covers small-bore applications from approximately 0.95 mm to 18 mm.
Typical applications include small valve bores, injector and hydraulic spool housings, bushings and reamed holes. It is suitable for machine shops, QC teams, maintenance workshops, refinery and petrochemical shutdown work, and oil and gas service operations in Kuwait.
Temperature can affect small-bore measurements. Steel expands by approximately 11.5 μm per metre for every 1 °C change. For a 10 mm part, a 10 °C temperature difference can therefore produce roughly 1.2 μm of dimensional change. Allow the workpiece and gauge to reach the same temperature before taking a final inspection reading.
For a larger bore range, the Mitutoyo 526-122 covers 0.3"–0.4".
Key Benefits
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Measures very small holes from 0.145"–0.29"
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Split two-point contact suited to small internal diameters
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Hard chrome contact point for a durable measuring surface
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0.0001" graduation for fine analogue measurement
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Digital upgrade possible with a customer-supplied Digimatic indicator
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Provides measured bore size rather than only pass/fail results
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Part of the Mitutoyo 526 series for small-bore inspection
Who This Product Is Best For
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Machine shops checking small valve bores
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QC teams measuring bore size, taper and ovality
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Maintenance teams performing precision bore inspections
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Engine, pump and hydraulic rebuild workshops
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Oil and gas maintenance and refinery service teams
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Buyers standardising small-bore inspection equipment on the Mitutoyo 526 series
How to Measure a Small Bore With This Gauge
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Select the appropriate contact for the nominal hole size.
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Set the gauge against a setting ring or master of known size.
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Insert the gauge carefully into the bore.
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Rock the gauge gently through the bore and identify the turning point on the indicator.
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Read and record the deviation from the reference size.
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Repeat the measurement at different depths and positions to check for taper or ovality.
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Keep the gauge and workpiece at the same temperature for final inspection readings.
Frequently Asked Questions
What range does the Mitutoyo 526-156 measure?
It measures internal diameters from 0.145"–0.29" (3.683–7.366 mm).
Is a dial indicator included?
The 526-156 is supplied with an analogue indicator. A customer-supplied Digimatic indicator can be used when digital readings are required.
Do I need a setting ring?
A setting ring or master of known size is recommended for setting the gauge before measurement and establishing a reliable reference.
Why is a split two-point contact useful for small holes?
The split two-point contact is designed for small-bore measurement and helps provide a controlled two-point measurement inside the hole.
Which model should I choose if my bore is outside the 0.145"–0.29" range?
Choose a model whose measuring range brackets the actual bore size. The 526-156 covers 0.145"–0.29", while the Mitutoyo 526-122 covers 0.3"–0.4".
Can the Mitutoyo 526-156 be recalibrated?
Yes. Periodic calibration through an ISO/IEC 17025-accredited calibration service can help maintain measurement traceability.
How should I store and care for the gauge?
Clean the measuring surfaces after use, keep the instrument protected from coolant and direct sunlight, avoid impacts or drops, and check the measurement reference regularly. Periodic calibration should be scheduled according to your quality requirements.
How do I order the Mitutoyo 526-156 in Kuwait?
Pricing is quote-based. Call or WhatsApp +965 9807 4888 with the model number and required quantity, and General Tech Services LLC will confirm pricing and availability.
