The invention relates to a balance wheel-hairspring oscillator (10) comprising: a balance wheel shaft (18) intended to be pivotably mounted on a frame of a timepiece; a balance wheel (12) secured to the balance wheel shaft (18); a hairspring (14) comprising an inner end (14a) secured to the balance wheel shaft and an outer end (14b) intended to be connected to a connecting member (16) to said frame, and a transmission member (20, 22) arranged to interact with an escapement. The balance wheel (12) and the hairspring (16) are arranged on either side of the transmission member.

The invention relates to a balance wheel-hairspring oscillator (10) comprising: a balance wheel shaft (18) intended to be pivotably mounted on a frame of a timepiece; a balance wheel (12) secured to the balance wheel shaft (18); a hairspring (14) comprising an inner end (14a) secured to the balance wheel shaft and an outer end (14b) intended to be connected to a connecting member (16) to said frame, and a transmission member (20, 22) arranged to interact with an escapement. The balance wheel (12) and the hairspring (16) are arranged on either side of the transmission member.

The method of manufacturing a timepiece shaft (1) includes grinding a ceramic piece, especially to form a balance shaft (1), having a functional portion (2a; 2b) including at least one part (221a; 221b) of a pivot-shank (22a; 22b) and/or at least one part (211a; 211b) of a pivot (21a; 21b), the first functional portion being made of ceramic and a first outer diameter (D1) of the first functional portion being less than 0.5 mm, or less than 0.4 mm, or less than 0.2 mm, or less than 0.1 mm.

A timepiece shaft (1), especially a balance shaft (1), comprising a first functional portion (2a; 2b) including at least one part (221a, 221b) of a pivot-shank (22a; 22b) and/or at least one part (211a, 211b) of a pivot (21a, 21b), the first functional portion being made of ceramic and a first outer diameter (D1) of the first functional portion being less than 0.5 mm, or less than 0.4 mm, or less than 0.2 mm, or less than 0.1 mm

A timepiece shaft (1), especially a balance shaft (1), comprising a first functional portion (2a; 2b) including at least one part (221a, 221b) of a pivot-shank (22a; 22b) and/or at least one part (211a, 211b) of a pivot (21a, 21b), the first functional portion being made of ceramic and a first outer diameter (D1) of the first functional portion being less than 0.5 mm, or less than 0.4 mm, or less than 0.2 mm, or less than 0.1 mm

An assembly (300) includes (i) a hairspring (2) made of a paramagnetic alloy including at least one of the following elements: Nb, V, Ta, Ti, Zr and Hf, notably an alloy including the elements Nb and Zr with between 5% and 25% by mass of Zr and an interstitial doping agent including oxygen, and (ii) at least one fastening part (1; 1′), notably two parts (1; 1′), in particular a stud (1) or a collet (1′), for an end (2a; 2b) of the hairspring (2), the at least one part (1; 1′) having a first portion (10; 10′) that is designed to come into contact with the hairspring (2) and that is made of titanium or titanium alloy or of tantalum or tantalum alloy, notably grade 2 titanium or grade 5 titanium.

An assembly (300) includes (i) a hairspring (2) made of a paramagnetic alloy including at least one of the following elements: Nb, V, Ta, Ti, Zr and Hf, notably an alloy including the elements Nb and Zr with between 5% and 25% by mass of Zr and an interstitial doping agent including oxygen, and (ii) at least one fastening part (1; 1′), notably two parts (1; 1′), in particular a stud (1) or a collet (1′), for an end (2a; 2b) of the hairspring (2), the at least one part (1; 1′) having a first portion (10; 10′) that is designed to come into contact with the hairspring (2) and that is made of titanium or titanium alloy or of tantalum or tantalum alloy, notably grade 2 titanium or grade 5 titanium.

A fastening stud (1) for one end of a hairspring, the stud having a first portion (10) designed to come into contact with the hairspring, the first portion being formed such as to have a first surface (10b) and a second bearing surface (10c) with the hairspring.

A fastening stud (1) for one end of a hairspring, the stud having a first portion (10) designed to come into contact with the hairspring, the first portion being formed such as to have a first surface (10b) and a second bearing surface (10c) with the hairspring.

Method for attachment of a last outer coil of a timepiece balance spring inside a groove provided in a balance spring stud, wherein the method includes the step of adhesive bonding the last outer coil of the timepiece balance spring by means of a fluid adhesive whose viscosity is comprised between 200 and 400 mPa.Math.s.