Lapping

Lapping is like when you color with your crayons on a paper really hard, back and forth, to make it very smooth and shiny. But instead of crayons, people use a special kind of paste called "lapping compound" and rub it on a surface that needs to be very smooth and flat. They usually use a flat piece of metal or glass called a "lapping plate" to help make the surface very even. It's kind of like ironing clothes, but for metal or glass instead of clothes! Lapping is important for things like making precision tools or making sure things fit together perfectly, so they work better and last longer.