This International Standard specifies the nominal dimensions of general-purpose single-start solid (monobloc) gear hobs with axial keyway or tenon drive of 0,5 to 40 module. These hobs are intended for the production of gears which conform to ISO 54 and present a 20° pressure angle in conformity with ISO 53. NOTE Solid hobs are those made from one solid piece of material, as opposed to hobs which have inserted blades.