Knives (10, 182) each include a handle (12, 184) having a blade (14, 90, 194) pivotally attached to the handle. The blade is movable between a closed position in which it is received within a groove (36, 192) of the handle and an open position. The blade has a working portion (38, 198) and a tang portion (44, 98, 204), which remains within the groove when the blade is in its open position. A locking pin (72, 208) extends transversely of the handle and blade and is movable along a pair of elongated openings (74, 216), and engages the tang portion (44, 98, 204) of the blade to lock the blade in its open position. A spring (78, 228) biases the locking pin toward the tang.