Starrett 68033 Outside Micrometer 6 Inch Friction Thimble

Product Description

The STARRETT 68033 is a mechanical outside micrometer designed for high-precision linear measurement of external dimensions. It covers a full 6-inch measurement range with a graduation of 0.0001 inches and a certified accuracy of 0.000050 inches, making it suitable for close-tolerance inspection work in machine shops, manufacturing, and maintenance environments. The thimble uses a friction-drive mechanism to apply consistent measuring pressure and prevent spindle overload. Flat anvil and spindle faces are constructed from solid carbide for wear resistance and long-term repeatability. A ring-style lock nut secures the spindle position when a reading is taken.

The 68033 is used wherever tight dimensional verification is required on cylindrical or flat stock, shafts, fasteners, or machined components. Typical users include machinists, tool-and-die technicians, quality-control inspectors, and precision maintenance trades. The satin chrome finish reduces glare under shop lighting. The instrument ships with a lock nut and a wrench, so no additional tooling is required for initial setup or field adjustment.

Key Features

• 6-inch maximum measurement range with 0.0001 inch graduation
• Accuracy of 0.000050 inches for close-tolerance inspection
• Friction thimble for consistent, repeatable measuring pressure
• Solid carbide measuring faces on both anvil and spindle resist wear
• Ring-type lock nut holds spindle position during reading transfer
• Satin chrome finish reduces glare and resists corrosion
• Includes lock nut and wrench for quick field adjustment

Compatibility

Designed as a general-purpose outside micrometer for standard bench and field measurement applications where a 6-inch range mechanical instrument with friction thimble is specified.

Installation Notes

Outside micrometers require no power or mounting, but should be stored in a protective case away from heat sources and cutting fluids to maintain calibration. Before use, clean anvil and spindle faces with a lint-free cloth and verify zero at the appropriate standard. Periodic calibration against a certified gauge block set is recommended to confirm continued accuracy. Do not force the thimble against the workpiece — allow the friction drive to control measuring pressure.