The invention relates to a capsule socket (21) of afilling machine for two-piece capsules (1), and to asocket system comprising such a capsule socket (21) anda capsule half of a two-piece capsule (1). Thetwo-piece capsules (1) have two capsule halves, each with acapsule base (4, 14) and with a capsule wall (5, 15).The capsule socket (21) comprises a main body (7) and,formed in the latter, A receiving space (8) for thecapsule half. The receiving space (8) has a baseportion (9), assigned to the respective capsule base(4, 14), and a circumferential wall portion (10) forcentering the capsule wall (5, 15). The receiving space(8) has a clamping portion (11) between the baseportion (9) and the circumferential wall portion (10),wherein the clamping portion (11) has a smaller freecross section than the circumferential wall portion(10). In the transition region from its capsule base(4) to its capsule wall (5), the capsule half has acapsule part diameter (D U). The clamping portion (11)has a free clamping diameter (D K), which is smaller thanthe capsule part diameter (D U).
