Spi 10-721-9 Mechanical Hole Micrometer 0.5 to 0.65 Inch

Product Description

The SPI 10-721-9 is a mechanical hole micrometer designed for precise internal bore measurement in the range of 0.5000 to 0.6500 inches. It delivers a graduation of 0.0002 inches and an accuracy of 0.0002 inches, making it appropriate for close-tolerance inspection work in machining, manufacturing, and mechanical service environments. The three-point contact design is self-aligning and self-centering, which reduces operator-induced error during measurement. Solid carbide measuring anvils provide long-term wear resistance. The ratchet stop thimble delivers consistent measuring force, limiting over-tightening and improving repeatability across multiple readings.

This hole micrometer is suited for dimensional inspection of precision bores, bushings, and cylindrical bores in light manufacturing, machine shops, and mechanical repair facilities. The 0.5000 to 0.6500 inch range makes it appropriate for small-diameter internal measurements where standard plug gauges or two-point bore gauges may not provide the required accuracy. A gage depth of 2.36 inches allows reach into most standard bore configurations. Installation and use do not require a power source, making it fully portable for bench or in-machine use.

Key Features

• Measurement range: 0.5000 to 0.6500 inches
• Graduation and accuracy: 0.0002 inches
• Three-point contact design — self-aligning and self-centering
• Solid carbide measuring anvils for extended wear life
• Ratchet stop thimble for consistent, repeatable measuring force
• Gage depth of 2.36 inches for reach into standard bores

Compatibility

Designed as a general-purpose mechanical hole micrometer for internal bore measurement applications requiring a 0.5000 to 0.6500 inch measuring range.

Installation Notes

This instrument is used by machinists, quality technicians, and precision mechanics performing dimensional inspection. Before use, zero the micrometer against the included or appropriate setting ring sized to the measuring range. Handle the carbide anvils with care to avoid nicks or contamination that could affect accuracy. Store in a protective case away from temperature extremes to maintain calibration integrity.