Process for forming integral spindle-axle tubes

A process for extruding an integral spindle and axle tube, comprising the steps of:

• positioning a relatively short, tubular blank within an open ended, tubular die having an inlet end through which the blank is inserted and an opposite extrusion end formed by an annular, inwardly extending, continuous shoulder forming a die extrusion throat through which the blank is extruded, and with the throat diameter being larger than the inner diameter of the blank;
• inserting a punch into the die inlet end, with the punch closely fitted within the die and having an annular shoulder engaged against the free end of the blank, and having a first punch extension closely fitted within the interior wall of the blank, and having a second punch extension of a smaller diameter than the blank interior diameter extended through part of the blank and die throat, and having a third punch extension, which is formed on the punch co-axial with and extending from the second punch extension, but of a smaller diameter than the second punch extension, with the punch shoulder and punch extensions being located co-axially with each other and also with the blank and die throat, and with the second punch extension being located between the first and third punch extensions;
• next moving the punch towards the die throat so that the punch shoulder rams the blank towards the die throat, and simultaneously aligns its second punch extension within the die throat to thereby extrude the lead end of the blank through the annular space between said second punch extension and the die throat to thereby form one thickened end of the metal tube;
• continuing moving the punch so that the first punch extension aligns with the die throat to thereby extrude the blank through the annular space between the first punch extension and the throat to form a relatively thin wall metal tube middle portion;
• then removing the punch from the die, and inserting a second tubular blank within the die in full end to end contact with the trailing end of the partially extruded blank;
• reinserting the punch in the die with its punch shoulder engaging the trailing end of the second blank, and with the punch first extension closely fitted within the second blank, so that the punch second extension is aligned with but spaced from the die throat, and the third punch extension is positioned within the die throat;
• moving the punch in the direction of the die throat to extrude a portion of the first, partially extruded, blank through the annular space between the die throat and third punch extension to form a relatively thick ring section adjacent the trailing end of the partially extruded blank, and thereafter proceeding with the step of moving the punch so that the second punch extension moves within the die throat and the second blank pushes the remainder of the first, partially extruded, blank through the annular space between the second punch extension and the die throat to form an inwardly thickened end portion on the trailing end of the first blank, and also, simultaneously extrudes an inwardly thickened end portion on the leading end of the second blank;
• then removing the extruded first blank and continuing and repeating the cycle on the second and successive blanks;
• on each removed extruded blank, swaging radially inwardly, to a uniform outside diameter which is less than the extruded tube external diameter, both the thick ring section and the tube trailing end portion, i.e., the portion located between the thick ring section and the trailing end of the tube;
• then swaging radially inwardly only said tube trailing end portion until its internal diameter is about the same as the thick ring section internal diameter and its outside diameter is less than the thick ring section outside diameter, to thereby form an integral spindle and axle tube.