Starrett 50681 Jack Screw 1-1/4 in Base 2-1/4 to 3-3/8 in Height

Product Description

The STARRETT 50681 is a jack screw designed to provide adjustable mechanical support during precision measurement, setup, and workholding tasks. It features a 1-1/4 inch base diameter and adjusts from a minimum of 2-1/4 inches to a maximum height of 3-3/8 inches, giving technicians and machinists the range needed to support irregularly shaped or elevated workpieces. This type of jack screw is a standard bench and surface plate accessory found in toolrooms, machine shops, and inspection departments. Weighing 0.563 pounds, it is compact and easy to position by hand before locking to the required height.

Jack screws like the STARRETT 50681 are used wherever a stable, height-adjustable support point is needed under a workpiece during layout, inspection, or machining setup. Typical applications include supporting castings, plates, or fixtures on surface plates and machine tool tables. The adjustable height range makes it suitable for supporting parts with varying thicknesses or stepped profiles without requiring additional spacers or shims.

Key Features

• Adjustable height range from 2-1/4 inches to 3-3/8 inches for flexible workpiece support
• 1-1/4 inch base diameter provides a stable footprint on surface plates and machine tables
• Compact design at 0.563 pounds for easy single-hand placement and repositioning
• Threaded screw mechanism allows precise height adjustment without additional tools
• Sold individually, suitable for use in sets for multi-point workpiece support

Compatibility

Designed as a standard jack screw for use on surface plates, machine tool tables, and inspection fixtures where adjustable point support is required.

Installation Notes

Jack screws are typically placed and adjusted by hand on a clean, flat surface before a workpiece is set down. Ensure the base and contact surfaces are free of chips or debris that could affect stability or mar the surface plate. No special tools or codes are required for setup, but proper three-point or multi-point support practice should be followed to prevent workpiece rocking or tipping during layout or inspection.