40 mm 45° InH 9 Valve Seat Cutters

40 mm 45° Valve Seat Cutter – InH9 Internal Pilot Bore

Professional valve seat cutter with a 40 mm cutting head and 45° cutting angle, designed for machining the primary sealing surface 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 45° cutter machines the primary valve seating surface, creating the sealing interface between the valve face and the valve seat while maintaining precise seat width and concentricity.

What it actually does:

Cuts the primary sealing surface of the valve seat. The 45° angle is the industry standard seating angle for most automotive, motorcycle and industrial engines, providing reliable sealing, efficient heat transfer and long valve life.

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 (45°):

• Machines the primary valve seating surface
• Provides a precise valve-to-seat seal
• Ensures efficient heat transfer from the valve to the cylinder head
• Used together with 30° and 60° (or 75°) cutters in multi-angle valve seat machining

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 45° cutter is the primary tool in the valve seat machining process, as it produces the final sealing surface. Top-angle and throat-angle cutters are then used to adjust the seat width and contact position according to the engine manufacturer's specifications.

Specification:

• Tool type: Valve Seat Cutter
• Head diameter: 40 mm
• Cutting angle: 45°
• Internal pilot bore: InH9
• Compatible pilot shank: Ø9 mm
• Pilot fit: H9 precision
• Application: Primary valve seat 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
• Excellent sealing surface finish
• Precise valve seat geometry
• Professional cylinder head rebuilding

Typical valve seat sequence:

• 30° (or 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