Starrett 68134 Mechanical Inside Micrometer 1 Inch

Product Description

The STARRETT 68134 is a mechanical inside micrometer designed for precision internal bore and hole measurements in professional metrology and machining applications. It features a ratchet stop thimble for consistent, repeatable gauging pressure and three self-centering contacts that automatically align the instrument for true readings. Accuracy is rated at 0.000150 inches with a graduation of 0.0003 inches, placing this tool firmly in the high-precision tier required for close-tolerance work. The measuring faces are solid carbide for long service life. This instrument is suited for machinists, tool-and-die makers, quality control technicians, and precision maintenance trades who require reliable inside measurement at the bench or in the field.

The 68134 covers a measurement range up to 1 inch (minimum measurement 20.00 mm) and accepts extension rods up to 6.0000 inches, extending reach for deeper bores. Gage depth is 2-5/8 inches. A 0.7500-inch setting ring is included for calibration verification. The instrument ships complete with a case, contacts, instructions, setting ring, and wrenches, making it ready to use out of the box. It is appropriate for residential and commercial machine shops, manufacturing facilities, and any precision maintenance environment where internal bore dimensions must be verified to tenths-of-a-thousandth tolerances.

Key Features

• Ratchet stop thimble ensures consistent measuring pressure for repeatable results
• Three self-centering contacts automatically align the micrometer for true bore readings
• Solid carbide measuring faces resist wear in high-use production environments
• Accepts extension rods up to 6.0000 inches for deep-bore access
• Includes setting ring (0.7500 inch diameter) for on-site calibration checks
• Complete kit includes case, contacts, instructions, setting ring, and wrenches

Compatibility

Designed as a standard mechanical inside micrometer for use in precision measurement applications requiring internal bore gauging up to 1 inch range with extension rod capability.

Installation Notes

This instrument should be handled by qualified metrology or machining personnel familiar with inside micrometer calibration and use procedures. Before measuring, verify calibration using the included setting ring and allow the tool to thermally stabilize in the work environment. Clean measuring faces with a lint-free cloth before each use. Store in the provided case to protect the carbide contacts and thimble mechanism from damage.