Starrett 68130 Mechanical Micrometer 3/8 Inch Range

Product Description

The STARRETT 68130 is a mechanical bore micrometer designed for precise internal diameter measurement in demanding shop and field applications. It covers a measurement range up to 0.3750 inches (8.00 mm minimum), with a graduation of 0.0003 inches and an accuracy of 0.000150 inches. The ratchet stop thimble delivers consistent measuring pressure for repeatable readings. Measuring faces are solid carbide for long service life under frequent use. This instrument is used by machinists, tool-and-die technicians, and precision measurement specialists who require tight-tolerance bore verification.

The 68130 is suited for internal bore measurement in precision machining, engine rebuilding, hydraulic component inspection, and quality-control applications. It accommodates a maximum extension rod length of 6.0000 inches, making it adaptable to a range of bore depths up to 2.25 inches gage depth. The setting ring included with the unit has a diameter of 0.3125 inches and enables accurate calibration before use. The kit ships complete with case, contacts, instructions, setting ring, and wrenches, so technicians can put it to work immediately.

Key Features

• Measurement range up to 0.3750 inches with 0.0003 inch graduation for fine resolution
• Accuracy rated at 0.000150 inches for tight-tolerance inspection work
• Ratchet stop thimble ensures consistent, controlled measuring pressure
• Solid carbide measuring faces resist wear on hardened and abrasive bore surfaces
• Three contact points for stable, centered readings in round bores
• Maximum extension rod length of 6.0000 inches extends reach into deeper bores
• Includes setting ring, contacts, wrenches, instructions, and protective case

Compatibility

Designed as an OEM-style precision measuring instrument for use in any application requiring internal bore measurement within the 0.3750 inch maximum range.

Installation Notes

This instrument is used by machinists and metrology technicians and does not require power or integration into a system. Before measurement, calibrate the micrometer using the included setting ring on a clean, stable surface. Keep the measuring faces free of chips, oil, and debris to maintain accuracy. Store in the provided case when not in use to protect the carbide faces and calibration.