Value Collection STC-20 Differential Screw 1/4-28 Hex Socket

Product Description

The VALUE COLLECTION STC-20 is a differential screw designed for use with indexable cutting tool assemblies. It features a 1/4-28 thread size with both right-hand and left-hand thread sections, allowing it to clamp and release indexable inserts through a single rotational motion. The hex socket drive accepts a 1/8 inch hex key for installation and removal. Overall length is 1.16 inches, with each threaded section measuring 0.45 inches. This screw is a standard consumable component maintained in tooling cribs and used by machinists and tool-and-die technicians in production and job-shop environments.

Differential screws are used in indexable toolholders across turning, milling, and boring applications. The dual-thread design allows secure clamping of carbide inserts without requiring separate clamping hardware in supported toolholder styles. This part corresponds to industry standard number STC-20 and is compatible with clamp-style indexable toolholders that specify this standard. Suitable for both manual and CNC machining setups where indexable insert retention is required.

Key Features

• Dual-thread differential design clamps indexable inserts with a single hex key turn
• 1/4-28 thread size with right-hand and left-hand sections each measuring 0.45 inches
• 1/8 inch hex socket drive for standard hex key installation
• Overall length of 1.16 inches fits standard STC-20 compatible toolholder pockets
• Sold individually; minimum order quantity of 10 units per order

Compatibility

Compatible with clamp-style indexable toolholders specifying the STC-20 industry standard differential screw. Verify toolholder documentation before ordering to confirm correct screw standard and thread specification.

Installation Notes

Installation is performed by qualified machinists or tooling technicians. Ensure the machine spindle is fully stopped and all energy is isolated before changing indexable inserts or associated hardware. Use a calibrated 1/8 inch hex key to seat and torque the screw into the toolholder pocket. Do not use power drivers on differential screws, as overtightening can damage the threaded pocket or fracture the insert.