Carmex SR0790H21 Indexable Thread Mill 0.79 in Alloy Steel

Product Description

The CARMEX SR0790H21 is an indexable thread mill designed for precision internal thread milling operations in metal components. It accepts one IE-style insert (size 21 mm) secured by a screw-clamp holding method, delivering repeatable thread geometry across production runs. The toolholder is machined from alloy steel for rigidity under cutting loads. A through-coolant design channels fluid directly to the cutting zone, extending insert life and improving chip evacuation in deep-hole applications. Overall length is 3.7 inches with a 0.75-inch shank diameter, making it compatible with standard 3/4-inch toolholding systems. Licensed machinists, CNC mill operators, and toolroom technicians are the primary users of this tool.

The SR0790H21 suits CNC machining centers performing internal thread milling on ferrous and non-ferrous workpieces. It is built for applications where a single-point tap would present breakage risk or where thread quality in blind and through holes demands fine process control. The 0.79-inch cutting diameter and 1.57-inch maximum hole depth define the working envelope for standard milling cycles. The SR toolholder style and K21 key designation allow straightforward insert indexing without special fixtures.

Key Features

• 0.79-inch cutting diameter for precise thread milling in standard bore sizes
• 1.57-inch maximum hole depth supports a wide range of thread lengths
• Through-coolant capability directs fluid to the cutting edge for thermal management and chip removal
• Screw-clamp insert holding method secures the IE-style 21 mm insert firmly under load
• Alloy steel toolholder construction provides rigidity and resistance to deflection
• 0.61-inch neck diameter provides clearance relief in tight-bore entry conditions

Compatibility

Designed to accept one IE-style insert in 21 mm size; insert screw designation S21 and key designation K21 apply. Fits 3/4-inch toolholder bores on standard CNC machining center spindles. Verify insert style and insert screw compatibility before ordering replacement inserts.

Installation Notes

Installation and setup should be performed by a qualified CNC machinist or toolroom technician familiar with indexable milling tools. Power down and lock out the machine spindle before seating or indexing the insert. Confirm the insert screw is fully torqued per the insert manufacturer's documentation before engaging the cut. Connect the through-coolant supply line according to the machine tool builder's coolant port specifications and verify flow before running the thread milling cycle.