Machine Screw

Machine screw is also called mechanical screw or bolt. According to different types of head and drive, people usually classify machine screw into many different types.
Different types of screw have different function, but the common funtion is to fasten and set one obejct to another.
According to the head types, people classfied them in to following:
Round head
Pan head
Countersunk head (flat head)
Half oval head
Etc.Accroding to the drive types, people classfied them in to following:
Sloted
Phillips ( Cross )
Hexagon socket
Phillips/Slot Combination
Trox
Etc.
The Phillips ( cross ) drive type screw contact area is wide than sloted drive, it is more easy to screw in object and less broken the drive. so it is mroe widely usded than the others drive types. Hexagon socket screw and trox drive type screw can be applied with large tightening torque, strong connection strength, and the head can be buried in the object; they are commonly used for the joints requiring compact structure and smooth shape.

Accroding to the standards, people classfied them in to following:
DIN 912 DIN 7991
Hexagon socket cap screw Hexagon socket countersunk head screw
DIN 7985 DIN 965
Phillips (cross) pan head screw Phillips (cross) countersunk head screw
DIN 85 DIN 963
Slotted pan head screw Slotted countersunk head screw
etc.
Property class ( grade ) :
4.8 grade, this grade is most applied, and the material usuall is carbon steel.
8.8 10.9 12.9 grade, these grade are applied for some object need hight strengh request oppelication
A2-70 grade is for Stainless steel 304 material
A4-70 grade is for Stainless steel 316 materail
etc.
Our screws are widely used on lock, plastic toys , electrict equitment and others place