Valve grinding is a machining process to remove imperfections from the valve and its seat by using an abrasive wheel to achieve the correct angles. Valve lapping is a last manual process that uses an abrasive compound to create a perfectly sealed, smooth surface between the valve and seat after the grinding process. Grinding is the initial shaping, while lapping is the finishing step to ensure a gas-tight seal. Valve Grinding
- Purpose: To correct imperfections, wear, and damage on the valve and valve seat, and to establish the correct angle for proper sealing.
- Process: A grinding machine with an abrasive wheel is used to cut the valve and seat to their correct angles. This is a multi-step process that typically involves coarse, medium, and fine grinding stages to remove material.
- Result: The surfaces are smooth but may have fine striations or a slightly rougher finish from the grinding action.
Valve Lapping 
- Purpose: To create a perfect, gas-tight seal between the valve and the valve seat by smoothing out any remaining imperfections left by the grinding process.
- Process: An abrasive lapping paste is smeared on the valve or seat. The valve is then manually rotated against the seat in a back-and-forth motion, gently twirling it.
- Result: A mirror-smooth, perfectly mating surface that ensures the combustion chamber is completely sealed.
Equipment for Valve Grinding and Lapping
| for flat seats | for conical seats | for sealing surfaces - gate valves | sealing surfaces - safety valves |
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