Model And Related Performance of Machine Screws

What are the types of commonly used screw head and groove types?

Head shape name:

Flat Countersunk Head、100deg Flat Countersunk Head、Oval Countersunk Head、Countersunk Trim Head Screws、Fillister Head、 Pan Head、Truss Head,Round Head,etc.

Slot type name:

Soltted Type、Phillips Type、Torx Type,Square Type,Pozidriv Type,etc.

Technical conditions:

1.  Thread UNC UNF, Pre plating accuracy level 2A.

2.  Material and process requirements:

● Non quenched material: carbon steel

● Process: No heat treatment

● Hardness requirement: 69-100HRB

● Hardened material: medium carbon steel or low carbon steel

● Process: Heat treatment

● Hardness requirement: 25-32HRC

● Corrosion resistant steel: ASTM F837 stainless steel standard

● Nonferrous metals: ASTM F468ASTM F837 standard

3.  Surface treatment:

● Machine screws that should not undergo surface treatment are called natural color (uncoated and uncoated)

● If electroplating protection is required on the surface, ASTM F1941 standard should be followed.

Classification, working principle and type of self tapping screws:

1.  Thread type: ordinary self tapping screw

Work performance: self tapping screw with thread forming

Working principle: When screwed into the prefabricated hole, the extruded material shifts, forming an internal thread connected to the screw

2.  Thread type: Self extruding self tapping screw

Work performance: Self tapping locking screws are called thread rolling self tapping screws

Working principle: The screw applies intermittent and periodic pressure on the thread crest to form a connected thread.

3.  Thread type: self cutting self tapping screw

Performance: Self cutting and self tapping screws

Working principle: Machining cutting grooves or edges at the end of the screw shaft.  The screw acts as a tap.

4.  Thread type: self drilling self tapping screw

Work performance: self drilling and self tapping threads

Working principle: Self drilling and self tapping screws achieve a one-time operation of drilling, tapping, and tightening.

5.  Thread type: Wall panel self tapping nail

Work performance: Equipped with dual lead rapid screwing into self drilling threads and a "horn head" shape

Working principle: It has a horn shaped head and a concave support surface, which can be squeezed into the wall without tearing the paper on the outer surface of the wall panel or damaging the gypsum core of the wall panel.