A sub-assembly of external parts including, coaxially with a first component and a second component compressing together a sealing and friction joint, and interposed therebetween, a bolt securing them together by axially blocking the first component, and a lower surface of which lies, in the assembled position, in the vicinity of an upper surface of the second component, which bolt includes a lower relief protruding axially from this lower surface towards the second component, arranged to either complementarily cooperate with an oblong groove which is partially of revolution that the upper surface includes, and interrupted by a stopper limiting the angular travel between the second component and the bolt within a turn, or else to constitute an angular stopper to an upper relief protruding from the upper surface of the second component and extending axially towards the bolt.

A dust-proof assembly includes a dust-proof net and a sealing net. The sealing net includes a support portion and a flexible sealing body, and the support portion is provided with a plurality of through holes. The dust-proof net and the support portion are arranged opposite each other, and the dust-proof net is connected to the support portion. The flexible sealing body is connected to the support portion and at least partially protrudes out of the dust-proof net.

A sub-assembly of external parts including, a bolt interposed between a first component and a second component compressing together a joint, securing them together by axially blocking the first component, and which cooperates with the second component to enclose a ball occupying a well of depth greater than its diameter, that an orientation housing in the second component or the bolt includes, framed by channels of depth less than its diameter, limited by stops, which ball can occupy, when subjected to the gravity field and/or a magnetic field, both an orientation housing and a complementary housing of depth less than its diameter, that the bolt or respectively the second component includes, for their relative drive by the ball when it is simultaneously braced on a channel and a complementary housing.

A sub-assembly of external parts including, coaxially with a first component and a second component compressing together a sealing and friction joint, and interposed therebetween, a bolt securing them together by axially blocking the first component, and a lower surface of which lies, in the assembled position, in the vicinity of an upper surface of the second component, which bolt includes a lower relief protruding axially from this lower surface towards the second component, arranged to either complementarily cooperate with an oblong groove which is partially of revolution that the upper surface includes, and interrupted by a stopper limiting the angular travel between the second component and the bolt within a turn, or else to constitute an angular stopper to an upper relief protruding from the upper surface of the second component and extending axially towards the bolt.

A sub-assembly of external parts including, a bolt interposed between a first component and a second component compressing together a joint, securing them together by axially blocking the first component, and which cooperates with the second component to enclose a ball occupying a well of depth greater than its diameter, that an orientation housing in the second component or the bolt includes, framed by channels of depth less than its diameter, limited by stops, which ball can occupy, when subjected to the gravity field and/or a magnetic field, both an orientation housing and a complementary housing of depth less than its diameter, that the bolt or respectively the second component includes, for their relative drive by the ball when it is simultaneously braced on a channel and a complementary housing.

Exterior sub-assembly for a timepiece or watch or piece of jewelry, comprising a first component and a second component, arranged for a bayonet fitting between two rims and two wings comprised in the first component and the second component, and able to occupy an assembled and indexed position of the first and second components, this sub-assembly including a third component in the form of a ring, inserted between the first and second components and comprising a ring-like element housed inside a groove of the first or second component, this third component including a rotational stop with respect to the first or second component, and a resilient area with radial relief, cooperating in an angular indexing arrangement with a lug of the first or second component which is free to rotate with respect to the third component.

Exterior sub-assembly for a timepiece or watch or piece of jewelry, comprising a first component and a second component, arranged for a bayonet fitting between two rims and two wings comprised in the first component and the second component, and able to occupy an assembled and indexed position of the first and second components, this sub-assembly including a third component in the form of a ring, inserted between the first and second components and comprising a ring-like element housed inside a groove of the first or second component, this third component including a rotational stop with respect to the first or second component, and a resilient area with radial relief, cooperating in an angular indexing arrangement with a lug of the first or second component which is free to rotate with respect to the third component.