Spi 10-740-9 Inside Micrometer Set 1.6-4 Inch

Product Description

The SPI 10-740-9 is a mechanical inside micrometer set designed for precise internal bore and hole measurement in precision machining, toolroom, and quality-control applications. The set covers a measurement range of 1.6 to 4.0 inches using a ratchet stop thimble mechanism that delivers consistent, repeatable gauging force on every reading. Solid carbide measuring anvils resist wear on hardened surfaces and extend service life in production environments. The self-aligning and self-centering design reduces operator error and speeds up measurement cycles. This set is handled by machinists, toolmakers, and quality inspectors who require traceable dimensional verification.

The 10-740-9 is suited for internal diameter measurement in manufacturing, job-shop, and inspection environments where bore sizes fall between 1.6 and 4.0 inches. The set includes one extension rod, three setting rings sized at 2.0, 2.8, and 3.6 inches, spanner wrenches, and a wooden storage case. The ratchet drive provides controlled thimble torque for consistent anvil contact. Six micrometer heads are included to span the full range without gap. The wooden case keeps all components organized and protected between uses.

Key Features

• Measurement range of 1.6 to 4.0 inches with a stated accuracy of 0.00025 inch
• Solid carbide measuring anvils for wear resistance on hardened bores
• Ratchet stop thimble for consistent gauging force on every measurement
• Self-aligning and self-centering anvil design reduces operator-induced error
• Three setting rings included at 2.0, 2.8, and 3.6 inch diameters for field calibration
• Complete kit includes extension rod, spanner wrenches, and wooden carrying case

Compatibility

Designed as an OEM-style mechanical inside micrometer set for toolroom, production, and quality-control use where internal bore measurement from 1.6 to 4.0 inches is required.

Installation Notes

Inside micrometer sets are used by machinists and quality technicians and require no power source or wiring. Before use, zero and verify the instrument against the included setting rings to confirm accuracy. Store the set in the provided wooden case when not in use to protect the carbide anvils and precision threads. Do not overtighten the thimble against bore walls; use only the ratchet stop mechanism to apply measuring force.