40 mm 15° InH 9 Valve Seat Cutters

40 mm 15° Valve Seat Cutter – InH9 Internal Pilot Bore

Professional valve seat cutter with a 40 mm cutting head and 15° cutting angle, designed for machining the upper relief angle of engine valve seats. 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 15° cutter forms the upper relief angle above the valve seating surface, improving airflow while allowing accurate control of the final seat width and seating position.

What it actually does:

Cuts the upper angle of the valve seat without machining the sealing surface itself. The 15° angle removes material above the seat to improve airflow into the combustion chamber and establish the correct multi-angle valve seat geometry.

Head diameter (40 mm):

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

Cutting angle (15°):

• Machines the upper relief angle
• Improves airflow into the combustion chamber
• Helps control valve seat width and position
• Commonly used with 45° and 60° 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:

This cutter is typically used as part of a three-angle valve seat machining process. A common sequence is 15° top angle, 45° seating angle and 60° (or 75°) throat angle, depending on the engine manufacturer's specifications.

Specification:

• Tool type: Valve Seat Cutter
• Head diameter: 40 mm
• Cutting angle: 15°
• Internal pilot bore: InH9
• Compatible pilot shank: Ø9 mm
• Pilot fit: H9 precision
• Application: Upper valve seat 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
• Smooth cutting performance
• Optimized valve seat geometry
• Professional cylinder head rebuilding

Typical valve seat sequence:

• 15° — Top relief angle
• 45° — Primary seating surface
• 60° or 75° — 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