Which type of locking washer should be used when surface damage is a concern?

The Belleville washer is the correct choice when surface damage is a concern because it is specifically designed to provide a locking mechanism while minimizing surface wear and deformation. Unlike other types of locking washers, the Belleville washer has a conical shape that allows it to exert a consistent load while accommodating variations in assembly tolerances and surface irregularities. This design helps maintain the joint integrity without creating excessive localized stress or damage to the mating surfaces.

In contrast, split washers may dig into the surface as they compress, potentially leading to scratches or indentations. Flat washers serve primarily as load distribution components but do not provide a locking effect by themselves. Star washers can grip and bite into the surfaces but can also cause significant damage due to their more aggressive design. Therefore, for applications where the integrity of the surface is vital, the Belleville washer effectively balances locking capability with the need to protect against surface damage.