40 mm 60° InH 9 Valve Seat Cutters

40 mm 60° Valve Seat Cutter – InH9 Internal Pilot Bore

Professional valve seat cutter with a 40 mm cutting head and 60° cutting angle, designed for machining the throat angle below the primary valve seat. The cutter features a precision InH9 internal pilot bore for interchangeable pilots with a Ø9 mm shank, ensuring accurate alignment with the valve guide.

Application:

Designed for precision valve seat machining during cylinder head rebuilding. The 60° cutter forms the throat angle beneath the valve seating surface, improving airflow into and out of the combustion chamber while allowing precise adjustment of the final valve seat width.

What it actually does:

Removes material below the primary seating surface to create the throat angle. This reduces flow restriction around the valve, improves gas velocity and helps position the valve seat correctly for optimum sealing and engine performance.

Head diameter (40 mm):

• 48 mm maximum cutting diameter
• Suitable for large valve seats
• Provides excellent rigidity during machining
• Produces smooth and accurate cutting performance

Cutting angle (60°):

• Machines the throat angle below the valve seat
• Improves intake and exhaust gas flow
• Helps control valve seat width and seating position
• Commonly used with 30° and 45° cutters

Internal pilot bore (InH9):

The cutter incorporates a precision H9 internal bore designed for interchangeable pilots with a Ø9 mm shank. The pilot fits inside the cutter and locates in the valve guide, keeping the cutter accurately centered during machining. This minimizes runout and ensures excellent concentricity between the valve guide and valve seat.

In practice:

The 60° cutter is typically used after machining the primary 45° seating surface. By enlarging the throat area beneath the valve seat, it improves airflow while allowing the seat width to be adjusted according to the engine manufacturer's specifications.

Specification:

• Tool type: Valve Seat Cutter
• Head diameter: 40 mm
• Cutting angle: 60°
• Internal pilot bore: InH9
• Compatible pilot shank: Ø9 mm
• Pilot fit: H9 precision
• Application: Valve seat throat angle machining
• Guide system: Interchangeable pilot

Internal pilot bore (InH9):

• Precision H9 internal bore
• Designed for Ø9 mm pilot shank
• Excellent concentricity
• Quick pilot replacement

Advantages:

• High machining accuracy
• Improved airflow characteristics
• Precise valve seat geometry
• Professional cylinder head rebuilding

Typical valve seat sequence:

• 30° (or 15°) — Top relief angle
• 45° — Primary seating surface
• 60° — Throat angle

Use for:

• Cylinder head rebuilding
• Valve seat machining
• Automotive engines
• Motorcycle engines
• Performance engine building

Limitations:

• Requires pilot with Ø9 mm shank
• Not intended for valve guide machining
• Not for drilling operations
• Use with suitable cutting lubricant