Eccentric anti-loosening screw device

A method of manufacturing and installing an eccentric anti-loosening screw device comprising the steps of:

• drilling wherein a hole is drilled through a central portion of an elongated, multi-sided member, and a diameter of the hole is about the same as that of the shank;
• cutting wherein a middle portion of the multi-sided member is spirally cut to form a surface of curved inclination, an angle of curved inclination is greater than a pitch of the shank to form two locking members;
• fixing wherein a middle portion the surface of curved inclinations of the locking members are engaged prior to rotating with respect to each other, a gap is formed between the locking members, a plurality of solder points are formed to temporarily fasten the locking members together, and an opening angle of the gap is calculated from a center of a circle;
• threads forming wherein a thread forming machine is used to form threads on an inner surface of the hole until a threaded hole is formed in each locking member, and the locking members form the fastening assembly which is threadedly secured onto the threaded shank;
• and
• installing wherein a screw is screwed through a workpiece to be fastened, the fastening assembly is threadedly put on the shank of the screw, a tool is clockwise rotated to turn a second locking member, the fastening assembly rotates to fasten the workpiece, the tool is clockwise rotated to turn the second locking member until the solder points are broken and the gap is increased, and an eccentric force is generated at a joining surface of a first locking member and the second locking member and it is exerted on the workpiece to fasten them together.