A straight tubular ferrous blank of a circular section, starting material of the invention is deformed in its section along its whole length and bent to form a fork with two legs or blades, the thus formed tubular fork is set in a sectional forming die of top and bottom molds; the die has a concave corresponding to a protuberant socket and has also at its end an opening into which a mandrel having a recess corresponding to the same protuberant socket is introduced; the tubular fork set in the sectional die is subjected to the oil hydraulic bulge-forming process together with the mandrel simultaneously forced into the opening to bulge-form the socket, and the desired front fork blank of the single unit type is obtained.