Abstract: Metal collar device of the type used for integrating a glass part and a metal part of different coefficients of expansion. The collar is circular and comprises a first portion intended to be in contact with the metal part, a second portion intended to be in contact with the glass part and a bonding portion placed between said first and second portions. The second portion is not as thick as the first portion and as the bonding portion, so that it can adjust to the expansion of the glass part by exerting stresses on the latter below the limit of resistance of said glass part.