A support (20) for mounting a paperboard yarn core (C) on a spindle assembly (SA) includes a proximal-end support member (30) for supporting a proximal end of the core and engaging it in a substantially non-slip manner, and a distal-end support member (50) for supporting a distal end of the core. The proximal-end support member (30) is configured to be mounted on a hub (H) of the spindle assembly. The support members locate the core substantially coaxially with respect to a rotational axis (A) of the spindle assembly. The proximal-end support member (30) is configured to automatically prevent or minimize slippage of the core with respect to the support member both in acceleration and deceleration or braking of the spindle assembly.