What is the purpose of a lapping stick?

A lapping stick is specifically used to spin valves during the valve reconditioning process. This is a crucial step in engine maintenance, where the purpose is to ensure a proper seal between the valve and the valve seat. By using the lapping stick, the technician can apply a fine grinding compound and then rotate the valve back and forth against the seat, which helps to achieve a smooth and even surface. This method can effectively remove imperfections and create a better fit, enhancing overall engine performance.

Other options indicate tasks that are not suited for a lapping stick. For example, valve installation and measuring valve clearance involve different tools and techniques. Cleaning valve surfaces may require a different cleaning method or tool, focusing more on removing carbon deposits or grime rather than the precision grinding facilitated by a lapping stick during the reconditioning process.