METHOD FOR MAKING HOLES IN ELONGATED PARTS Russian patent published in 2003 - IPC

FIELD: plastic metal working, possibly manufacture of gun barrels and gun powder mounting tools. SUBSTANCE: method comprises steps of making in elongated parts openings with sharply increased diameter or dead opening; forming on blank with preliminarily made lengthwise opening cone portions in zones corresponding to sharply increased diameter of opening or to bottom of dead opening; in order to realize it, changing outer diameter of blank and inner diameter of its opening; then placing blank on mandrel and performing its omnidirectional pulsating lateral squeezing by means of hammers; making cone portions with inclination angle relative to lengthwise axis of blank opening in range 10 -20 degrees. It is possible to form cone portions by lowering outer diameter of blank in zone corresponding to small diameter of opening or to absence of such diameter in dead opening and by increasing inner diameter of blank opening in zone after increased diameter or bottom of dead opening. EFFECT: enlarged manufacturing possibilities of method. 4 cl, 2 dwg, 1 ex