Seco 00040974 Mtjn Indexable Turning Toolholder 3/4 in

Product Description

The SECO 00040974 is a right-hand MTJN-style indexable turning toolholder designed for use on CNC lathes and manual turning centers. It accepts TN..33. series inserts secured by a clamp and pin Multiple Lock holding method, providing rigid, repeatable insert seating during interrupted and continuous cuts. The shank measures 0.75 inches wide by 0.75 inches tall, with an overall length of 4.5 inches and a head length of 1.12 inches. The negative rake geometry at -5 degrees suits harder workpiece materials and heavy-duty turning applications where edge strength is the priority.

This toolholder is suited for general-purpose turning operations in production and job-shop environments. It is compatible with a universal range of workpiece materials, covering ISO material groups H, K, M, N, P, and S, making it a versatile holder for shops running steel, stainless, cast iron, non-ferrous, and superalloy parts. The right-hand cutting direction and 3-degree lead angle orient the insert for standard turning passes moving toward the spindle headstock. It is installed by machinists and CNC setup technicians in both prototype and production turning cells.

Key Features

• MTJN toolholder style with right-hand cutting direction and -5-degree rake angle
• Multiple Lock clamp and pin insert holding method for secure, rigid insert retention
• Accepts TN..33. inserts with a 0.375-inch inscribed circle
• 3/4 inch by 3/4 inch square shank fits standard toolpost and turret pockets
• Steel construction provides durability under continuous and interrupted cutting loads
• Universal material compatibility across ISO groups H, K, M, N, P, and S

Compatibility

Designed to accept TN..33. series inserts with compatible insert size code TN33 and a 0.375-inch inscribed circle. Fits standard toolpost and turret pocket configurations sized for a 3/4 inch by 3/4 inch shank.

Installation Notes

Installation is performed by a qualified machinist or CNC setup technician. Power down and lock out the machine before mounting or removing the toolholder from the turret or toolpost. Ensure the turret pocket and shank contact surfaces are clean and free of chips before seating the holder. Follow the machine tool manufacturer torque specifications for clamping fasteners and verify insert seating before returning the machine to operation.