Collar sleeves and process and tool for the manufacture thereof

A process for the manufacture of a collar sleeve consisting essentially of a relatively hard substrate having an inner surface coating of relatively softer bearing material, said process comprising the steps of preparing a cylindrical sleeve of said substrate having an inner surface coating (4) of bearing material except in a cylindrical region (6) at one end where the collar is to be formed;

• placing the said prepared sleeve in a radially confining cylindrical die recess (12) with the other end in axial abutment with a first die part (13) and with the said one end projecting above the recess into a coaxial cylindrical die bore (19) of larger diameter than said recess, providing another die part (14) extending through said die bore into said recess, said other die part having a first cylindrical section (16) fitting slidably within said one end region of the sleeve and a second cylindrical section (15) extending through the remainder of said sleeve and an axially facing surface (25) above said sections in abutment with said one end of the sleeve;
• relatively axially moving said die parts together with upsetting pressure to shorten said sleeve and said coating simultaneously in the axial direction to calibrate the said sleeve and said coating between said confining die recess and said second cylindrical section of the other die part and to simultaneously increase in radial thickness said one sleeve end region within said coaxial die bore to form an integral radially thickened collar (7) on said one sleeve end.