Shoemakers drive clinching nail fasteners through upper material, bottom material, or both, into last plate on the bottom of of last. The pointed tips of the nails strike the plates and bend over, forming small hooks. The nails then hold the material in place from both ends: the head on one, the clinched point on the other. The protruding metal hooks of clinching nails within the uppers are often covered with a sock liner so the foot doesn’t rest on them directly.
Shoes built this way nearly always include sock liners or lay-in footbeds to cover the exposed, peened-over points of the nails on the top of their insoles.
Clinching nails offer a somewhat heavier, but potentially sturdier, alternative to wood pegs in many applications. Unlike clinching nails, pegging does not require a last plate. Clinching nails may be used in the seat of a shoe without a plate, then clinched over with a drift or punch through the throat of the shoe after delasting. Pegs, by contrast, can be used through the waist or even in the forepart, regardless.