Abstract: A knife block for use in a fine gauge tufting machine carries four knives, disposed in pairs on opposite sides of a central web with their edges engaged in opposed pairs of grooves in the block. The knives are retained in the block by two knurled cylindrical clamping blocks, which are disposed in slots in the block and are pressed by clamping screws into engagement with the edges of the knives.

Abstract: A knife assembly for a tufting machine includes a knife bar; a plurality of knife blocks mounted side by side on the knife bar; projecting pegs extending from the knife blocks which are each inserted into one hole of a row of uniformly spaced retaining holes in one side of the knife bar; clamping screws for retaining the pegs in the holes; and a row of uniformly spaced pins carried by the knife, or a plate attached to the knife bar, which engage corresponding slots in the faces of the knife blocks from which the pegs project to determine the orientation of the blocks with respect to the knife bar, the pins being laterally offset by the same amount with respect to the retaining holes; and knives mounted in the knife blocks.