Equipment for metal hardware, fasteners and component parts сold production

return to main page equipment for cold heading

FOLDER head INFO
  • Design of fasteners
 

Equipment for metal hardware, fasteners and component parts сold production
SCREWS VARIETY

(for reference)

 

The screwing ability to any material appears due the thread on the screw rod.

Screw thread differs from bolts thread. It is higher and has larger cutting pitch. The threaded part of the screw has a conical shape tapering towards the end of the screw. Threads can be cut either along the entire length or only on part of the screw. Screws dimensions are also varied depending on the tasks to be solved with their help.

Thus, a very small size screw, 8 mm length and 4 mm in diameter, is used for example, for fixing nameplates to the finished product. At the same time, for fastening railway rails to the sleepers, the so-called track screw is used it has length of 170 mm and diameter of 24mm.

Screws have different head shapes. Their shape is determined by the requirements to the mounting structure, conditions of installation and appearance of the product.


Heads shapes are shown in Fig. 1.

 

screws

Figure 1 Types of heads and slots of screws

 

  • Flat. After the installation it is completely recessed in the fastened element material and maintains the smooth surface.
  • Double flat. Strong kind of flat head withstanding heavy loads during installation in solid materials as by screwing, so by stroking
  • Truncated flat. Variation of flat head allowing more efficient press of the fastened element to the base material by increasing the length of the fastener thread and hard bottom area on the head, the surface of which is perpendicular to the action of plucking.
  • ""Horn" flat. ". Variation of flat head providing efficient snuggling of the drywall to base material . The special curved horn-like shape of the head withstands plucking, that influence fixed sheet of drywall.
  • Round head. Effectively keeps fastened element thanks to the wide support surface. It is used where there is no need to maintain an even surface of the fastened element.
  • Round head with pressure pad. Variation of the round head with enlarged bearing surface and reduced height. With enlarged bearing surface this kind of head is perfect for fastening sheet materials.
  • Narrow cylindrical head. It has a minimal bearing surface, but when mounting is completely recessed in fastening elements. It is used in fasteners fixing as base material, as fastening elements by means of the thread.
  • Trapezoid head. It has enlarged bearing surface, on the inner side are locking notches.
  • Hexagon head. One of the oldest forms of fasteners heads, standardized under the appropriate spanner sizes. Today for hex heads mounting by means of an electric tool special hexagon conductors are used.
  • Hexagon head with with pressure pad. It has the same function as a simple hexagon head, but has slightly larger bearing surface.

In order to screw the fasteners by means of tools such as screwdriver in the screw heads there are slots. Slots may be:

  • Recess
  • Cross
  • Combined
  • Hexagram
  • Internal hexagon
  • Hexagon

 

The traditional material for screws manufacturing is ST 08 and ST 10 steel.