Machine for manufacturing variable ratio racks

A machine for manufacturing variable ratio steering gear racks having teeth in two groups arranged symmetrically about a central point on the rack, said machine comprising a base, a holding fixture to hold at least one rack blank having a longitudinal axis and indexable about a second axis passing at right angles to the longitudinal axis of the rack blank through said central point of a rack blank held in said fixture, a broach carrying member, a plurality of pairs of broach blades spaced apart at length along said broach carrying member, means for producing relative movement between said broach carrying member and said holding fixture, said pairs of blades being arranged to cut sequentially pairs of corresponding teeth of said groups of teeth simultaneously on the occurrence of said relative movement, means to hold said holding fixture correctly indexed during the cutting of teeth, means to index said holding fixture about said second axis after each pair of corresponding teeth has been cut preparatory to the cutting of a succeeding pair of teeth.