Description
The SECO 75056399 is a right-hand MWLN-style indexable turning toolholder designed for external turning operations on CNC lathes and manual turning centers. It uses a clamp and pin holding method to secure WN..33. series inserts at a negative rake angle of -5.44 to -6 degrees, providing stable, rigid cutting with controlled chip formation. The shank measures 0.625 inches wide by 0.625 inches tall, and the overall length is 4 inches. Licensed machinists and CNC operators install this holder in production and job-shop turning applications where insert security and repeatability are priorities.
This toolholder is suited for right-hand external turning on a broad range of workpiece materials, including steel, stainless, cast iron, aluminum, non-ferrous alloys, and high-temperature alloys, corresponding to material codes H, K, M, N, P, and S. The negative rake geometry makes it appropriate for interrupted cuts and harder materials where edge strength is critical. The 4-inch overall length and 0.875-inch back-of-bar to cutting edge dimension position it as a standard shank holder for common tool turret and block tooling setups.
Key Features
- MWLN toolholder style with negative rake angle (-5.44 to -6 degrees) for strong, stable cutting edge engagement
- Clamp and pin insert holding method for secure, repeatable insert positioning
- Compatible with WN..33. series inserts with a 3/8 inch (0.375 inch) inscribed circle
- Right-hand cutting direction with 0.625 inch x 0.625 inch square shank
- Universal workpiece material compatibility covering steel, stainless, cast iron, aluminum, non-ferrous, and superalloys
- Steel toolholder construction for rigidity and long-term dimensional stability
Compatibility
Designed for use with WN..33. series indexable inserts with a compatible insert size code of WN33 and a 3/8 inch inscribed circle. Part of the SECO Multiple Lock series. Also referenced under catalog number MWLNR L103A.
Installation Notes
This holder is installed by machinists on CNC or manual lathes in a turret, gang plate, or block toolholder position. Before changing inserts or mounting the holder, power down the machine and engage the spindle lock per standard machine tool safety procedures. Use calibrated torque tools when tightening the clamp screw to avoid cracking the insert seat. Verify tool centerline height against the spindle centerline before taking the first cut.
Technical Specifications
- Toolholder Style: MWLN
- Hand of Holder: Right Hand
- Cutting Direction: Right Hand
- Rake: Negative
- Rake Angle: -5.44 to -6 degrees
- Shank Width: 0.625 inches
- Shank Height: 0.625 inches
- Overall Length: 4 inches
- Head Length: 1.2 inches
- Back of Bar to Cutting Edge: 0.875 inches
- Insert Compatibility: WN..33.
- Insert Inscribed Circle: 0.375 inches
- Insert Holding Method: Clamp and Pin
- Compatible Insert Size Code: WN33
- Primary Workpiece Material: Universal (H, K, M, N, P, S)
- Toolholder Material: Steel
- Series: Multiple Lock
- Coolant Through: No
- Weight: 1 pound
Standard Information
- Brand: SECO
- Manufacturer Part Number: 75056399
