Starrett 49509 Electronic Drop Indicator 1 Inch

Product Description

The STARRETT 49509 is an electronic drop indicator with a 1-inch maximum measurement range, designed for precision dimensional gauging in machining, toolroom, and quality control environments. The LCD display provides clear numeric readout in both inch and metric units. Accuracy is rated at 0.0001 inch (0.0020 mm), with selectable resolution down to 0.00005 inch. The flat back design allows the indicator to seat flush against magnetic bases and surface plates without rocking. Two lithium CR2032 batteries are included. This instrument is used by machinists, tool and die technicians, and metrology personnel who need reliable, repeatable contact measurement on machined surfaces, fixtures, and assemblies.

The 49509 is suited for setup and inspection tasks in precision manufacturing, job shops, and quality labs. The 3/8-inch stem diameter fits standard indicator holders, clamps, and magnetic base arms commonly found in machine shop and inspection environments. Both inch and metric modes make it adaptable across mixed-standard workflows. The selectable resolution settings allow the user to match display sensitivity to the task, from coarse runout checks to fine surface comparison work.

Key Features

• 1-inch measurement range with 0.0001-inch accuracy
• LCD display with selectable inch and metric readout
• Multiple resolution settings: 0.00005, 0.0001, 0.0005, and 0.001 inch
• Flat back included for stable mounting on surface plates and magnetic bases
• 3/8-inch stem diameter fits standard indicator holders
• Includes two lithium CR2032 3V batteries — ready to use out of the box

Compatibility

Designed for use with standard 3/8-inch stem indicator holders, magnetic bases, and surface plate fixtures common in toolroom and quality control applications.

Installation Notes

Mounting is performed by securing the 3/8-inch stem in the collet or clamp of a compatible indicator holder or magnetic base arm. Ensure the contact point is perpendicular to the measured surface to avoid cosine error that reduces reading accuracy. Zero the display after positioning before taking measurements. Battery replacement requires a CR2032 coin cell — do not short or dispose of lithium cells in general waste.