Sub-assembly of external parts for timepiece or watch or a piece of jewellery

A sub-assembly of external parts for a timepiece or for a watch or for a piece of jewellery, comprising, coaxially with a first component and a second component compressing together at least one sealing and friction joint, and interposed therebetween, a bolt securing them together by axially blocking said first component, and a lower surface of which, in the assembled position, directly faces an upper surface of said second component,

• wherein said lower surface is arranged to cooperate with said upper surface to enclose a ball arranged to occupy, in a static rest position, a well of depth greater than a diameter of said ball that an orientation housing in said second component or said bolt includes, the well being framed by channels of depth less than the diameter of said ball and limited by limitation borders, and
• wherein the ball is configured to occupy, during an adjustment where the ball is subjected to a gravity field and/or a magnetic field, both an orientation housing in said second component and a complementary housing in said bolt, the complementary housing having a depth less than the diameter of said ball, for a relative drive between said second component and said bolt by said ball when said ball is simultaneously braced on said channel and said complementary housing.