Board member fastener

A board member fastener used to affix a first board member and a second board member together, said first board member providing a first through hole, said second board member providing a second through hole, said board member fastener being inserted into said first through hole and said second through hole and punch impacted so that said board member fastener, said first board member and said second board member are affixed together to eliminate the gap between said first board member and said second board member, said board member fastener comprising a through hole inside, an inner taper surface located above said through hole and in the shape of a funnel that is inclined outward and upward, a planar force-bearing portion connected outside said inner taper surface, an outer taper surface connected to an outer side of said planar force-bearing portion away from said inner taper surface and inclined outward and downward in a different direction and at a different angle relative to said inner taper surface, a vertical outer ring surface connected below said outer taper surface, a beveled surface connected below said vertical outer ring surface and inclined in a different direction and at a different angle relative to said outer taper surface, a straight cylindrical deformation portion connected below said beveled surface, which is deformed and pressed in said first through hole and said second through hole when said board member fastener is punch impacted, a bottom portion with reduced outer diameter connected below said straight cylindrical deformation portion, and a ring groove recessed between said straight cylindrical deformation portion and said bottom portion so that when said board member fastener is impacted by stamping, said ring groove is used to deform, fit and be fixed to said second board member.