Two-for-one twisting spindle having a pneumatically actuated threading device

Two-for-one twisting spindle having a pneumatically actuated threading device for a thread, with a spindle shaft which can be rotated about its vertically arranged rotational axis and is partially configured as a hollow shaft and, in the lower part, has a feed bore extending coaxially to the rotational axis, and with an injector element, which opens into a thread guide channel of a thread guide ring and which, during the threading process, can be temporarily connected by means of a compressed air feed to a compressed air source, a part of the compressed air feed to the injector element being formed by the feed bore, characterized in that the compressed air feed comprises a connection element (27) with a curved air channel (26), which connects the feed bore (24) to the injector element (16) and in that the connection element (27) is configured as a separate component and the air channel (26) is adapted to the flow requirements.