Planing wood typically reduces overall dimensions by about how many millimetres?

• A. 1
• B. 2
• C. 3
• D. 4

Answer: (C)

Planing removes material in thin shavings to smooth and true the surface. Each pass takes off only a small amount, so the overall reduction in dimensions is usually about three millimetres. A lighter change like 1–2 mm is often not enough to finish the surface, while 4 mm would be more than typical and could overshoot the target dimension. So, three millimetres is the common amount you’d expect.