This pressure riveting screw nut phenomenon not normally
There are two reasons: first because the fastener product itself quality problems;
Second because the installation fasteners damaged screw thread, the thread of the phenomenon to appear.

What is the rivet nut column? Rivet nut column called rivet nut column or column nut, is a fastener used in sheet metal, sheet metal, chassis, cabinets, rivet nut column and its shape end is hexagonal, the other end is a cylindrical shape, the middle six angle sides and a cylindrical a tool withdrawal groove