Starrett 53056 Mechanical Tubular Micrometer 40 in

Product Description

The STARRETT 53056 is a mechanical tubular micrometer designed for large-diameter and deep-reach measurement work. It covers a 40-inch measurement range with 0.001-inch graduation and an accuracy of 0.0001 inches, making it a reliable tool for precision layout and inspection tasks. The friction thimble provides consistent measuring force to reduce operator-induced error. A satin chrome finish resists corrosion and glare under shop lighting. This instrument is intended for use by machinists, tool-and-die makers, metrology technicians, and precision fabricators who require accurate measurement across extended ranges.

This micrometer is suited for applications requiring measurement of large workpieces, bore depths, or tubular stock where a standard micrometer falls short. The 40-inch range is achieved through a system of 10 extension rods, each with a 3/8-inch (9.53 mm) diameter, that allow the user to build up the required measurement reach incrementally. The hardened and ground anvils on the rods are adjustable for length, ensuring contact integrity across the full range. This setup is commonly used in machine shops, tool rooms, and industrial inspection environments.

Key Features

• 40-inch measurement range achieved via 10 interchangeable extension rods
• 0.001-inch graduation for precise readings
• 0.0001-inch accuracy for demanding inspection work
• Friction thimble for controlled, repeatable measuring force
• Hardened and ground anvils on rods, adjustable for length
• Satin chrome finish for corrosion resistance and reduced glare

Compatibility

Designed as an OEM-style precision measuring instrument compatible with standard tubular micrometer extension rod systems using 3/8-inch diameter rods.

Installation Notes

This instrument is used and calibrated by qualified metrology personnel or precision machinists. Before use, verify all extension rod connections are fully seated and the anvil surfaces are clean and free of debris. Periodically check calibration against a certified gauge standard, particularly after rod changes or any impact to the instrument. Store in the provided case to protect the satin chrome surfaces and rod threads from damage.