Abstract: A heavy-duty hob for hobbing gears comprises a cylindrical body formed in its peripheral surface with generally axially extending grooves, and tooth-carrying bars, which extend in said grooves and carry cutting teeth which radially protrude from said body and constitute a helical array around the body. It is an object of the invention to avoid the disadvantages of known hobs, to provide the hob with easily replaceable cutting tips, and to permit the use of stable bar-shaped cutting tips which have no through bores and can be used in a plurality of positions and regardless of the module of the gear to be cut extend throughout the length of that side face of the associated tooth which engages the cutting tip.