What is the purpose of shimming in carpentry?

Shimming is a critical technique in carpentry that is primarily used to level or align frames, doors, or windows. When constructing or installing these elements, it is common for surfaces to be uneven or misaligned due to settling, wear, or differences in material thickness. Shims, which are typically made of wood or plastic, are thin wedges inserted into gaps to fill voids and create a flush surface. This ensures that doors and windows open and close smoothly without binding or sticking, and that frames are square and plumb, which is essential for structural integrity and aesthetic finish. Proper shimming helps achieve accurate measurements and alignment, which are fundamental to the overall quality of the carpentry work.