Abstract: This invention relates to machines for softening leather, commonly referred to as staking machines, of the type in which leather to be staked is passed between opposed interengageable processing elements the distance between which is periodically increased and decreased by relative movement of the processing elements. The leather is staked by the action of the processing elements as they approach their minimum distance apart. The construction of the machine is such that the processing elements both execute a periodic motion around closed paths e.g. circular paths. The movements of the two processing elements around their closed paths are mechanically synchronized. Thus, the leather is processed and is simultaneously transported by the movement of the processing elements.