Abstract: Two matrices, each bearing modulation to form a microgroove disc record, are fixed to half-moulds by means of sleeves, having first and second fixing flanges which extend into the gap between the matrices. One of the flanges is an annular blade whose inner radial surface defines the edge of a moulded disc and whose thickness is slightly less than that of the moulded disc. Formed integrally with, or attached to, the blade is a group of radially outwardly extending lugs which are attached to the body of its associated sleeve. The other flange comprises a second group of lugs mounted to the body of its associated sleeve radially outward of the blade such that the second group of lugs may lie in the spaces between the first mentioned group of lugs. The thickness of the lugs of the second group determines the thickness of the disc and the thickness of the lugs of the first and second groups differs, to determine a gap for escape of air along the first flange.