Making rings from tube stock

A method for in succession making rings from tube stock, including the steps of:

• (i) supporting the tube stock on a central axis and effecting relative rotation about the central axis as between the tube stock and a part-off type rolling tool capable of limited, controllable axial movement, whilst
• (ii) advancing the rolling tool in a generally radial direction into the tube stock to form a circumferential parting groove to a depth approximately equal to the required wall thickness of the ring;
• (iii) stopping the advance of the rolling tool just in time to avoid complete severance of an annular end portion from the tube stock by the rolling tool;
• (iv) subsequently completing severance of the end portion to constitute a said ring;
• (v) after stopping the advance of the rolling tool but whilst the end portion is not yet fully severed, machining the unsevered circumferential surface of the end portion to its required diameter;
• (vi) radially retracting the rolling tool;
• and
• (vii) axially feeding the tube stock forward ready for making the next ring;
• characterised in that a grooving tool is advanced in a generally radial direction simultaneously with the rolling tool, to form on the tube stock a substantially V-shaped, circumferential locating groove spaced axially from the parting groove by a predetermined distance with the parting groove lying between the locating groove and the annular end portion, the tube stock in step (vii) being fed forward by an amount approximately equal to said predetermined distance so that the locating groove lies opposite the rolling tool, and the rolling tool being guided by the locating groove at the commencement of its next advance into the tube stock, so as to be in exact register with the locating groove.