Abstract: A drum cutter for paper cutting operations has a series of bar-like cutter inserts at angularly spaced positions around its periphery. The inserts are indexable and are held by clamping elements that engage them at points spaced from their ends to draw them radially inwards against bearing faces on the cutter drum or on support members which are themselves detachably mounted on the drum. The clamping elements are tightened by screws extending axially into each end of the drum. The inserts are clamped against bearing surfaces which are at a smaller radius in a region between the clamping elements than they are in end regions beyond the clamping means, so as to give the operative cutting edge a concave profile.