Complex sentence: For example, pieces of shot may be placed between the wood pieces to produce indentations when the pieces are clamped together; after the clamp is released, the indentations indicate the center points for drilling.
Split into simpler sentences: For example, pieces of shot may be clamped between the pieces of wood to be joined before drilling. After the clamp is released, the marks left by the shot can be used as the center points for drilling.