Spi 11-568-3 Mechanical Depth Micrometer 4 Inch 4 Rods

Product Description

The SPI 11-568-3 is a mechanical depth micrometer designed for precise depth measurement in machining, toolroom, and inspection applications. It features a 4-inch measurement range, a ratchet stop thimble for consistent measuring pressure, and a rotating rod system with 0.001-inch graduation. Accuracy is rated at 0.0002 inches, and the unit arrives NIST certified with a short-form certificate of calibration included. The 4-inch base length provides a stable reference surface across wider workpieces. This instrument is used by machinists, quality control inspectors, and toolroom technicians who require traceable, repeatable depth readings.

The 11-568-3 suits general-purpose depth measurement on stepped bores, slots, keyways, and counterbores in both production and inspection environments. The set includes four interchangeable rods to cover the full 4-inch range, allowing the technician to select the appropriate rod for the depth being measured. The ratchet stop thimble standardizes applied force, reducing operator-to-operator variation. This micrometer is appropriate for use on metal, plastic, and composite workpieces where tight tolerances must be verified and documented.

Key Features

• 4-inch maximum measurement range with four interchangeable rotating rods
• 0.001-inch graduation for fine, readable incremental measurement
• Accuracy rated at 0.0002 inches for high-precision inspection work
• Ratchet stop thimble ensures consistent measuring force across readings
• 4-inch base length provides a broad, stable reference surface
• NIST-certified calibration with traceability certificate and case included

Compatibility

Designed as a standard mechanical depth micrometer for use in toolroom, production, and quality inspection settings where traceable dimensional verification is required.

Installation Notes

Depth micrometers should be handled and stored in the supplied case to protect the calibrated surfaces. Before use, verify the zero reference against a flat reference surface and confirm the calibration certificate is current for your inspection records. Do not overtighten the thimble lock or apply lateral force to the rods, as this can affect accuracy and rod straightness. Periodic recalibration to a NIST-traceable standard is recommended per your facility's quality management procedures.