1. Top view of fillister head screw.

2. Cold upset female die of fillister head is the key mold in the manufacturing process of heading bolt.

3. The fillister in both sides of the needle-bar can protect and carry fabrics and reduce puncture force.

4. Side view of fillister head slotted screw with adjustable thread length.

5. Top view of fillister head screw. Selection box represents thread diameter.

6. After natural cooling, metal tube is embedded into the long crus fillister, and the top of the metal tube side is under the welding face of the carrying surface.