Mechanical locking system for building panels

A set of panels comprising a first panel and a second panel, a panel edge of the second panel being insertable into a core groove of the first panel to obtain a mechanical connection between the first panel and the second panel,

• said first panel comprising a first main plane and said second panel comprising a second main plane, the panel edge being insertable into the core groove by an essentially linear relative displacement of the first and second panels when the first main plane is essentially parallel to the second main plane,
• said panel edge comprising a separate and flexible tongue and said first panel comprising a tongue groove, wherein the separate and flexible tongue is insertable into the tongue groove for connecting said panels to each other in a first direction, which is parallel to the first main plane,
• wherein the panel edge of the second panel is configured to cooperate with the core groove of the first panel for connecting said panels to each other in a second direction, which is perpendicular to the first main plane,
• wherein a longitudinal direction of the separate and flexible tongue extends parallel with said panel edge and/or core groove, and
• wherein the separate and flexible tongue is arranged in an insertion groove, said separate and flexible tongue being displaceable inwardly towards a bottom of the insertion groove and outwardly into the tongue groove during a locking of the first and second panels,
• wherein the insertion groove is inclined with respect to said second direction.