Big flat head machine screws

a) It is a standard that defines the specifications for cross recessed raised cheese head screws (Pan Head). These screws have a raised cylindrical head with a flat bearing surface and a cross recess, often referred to as a Phillips drive (Type H). Some other common types are cross recess type Z (Pozi) and Generic hexalobular socket / 6 lobe. 

a) ISO 7380-2 specifies the standard for hexagon socket button head screws with collar. Generic hexalobular socket (6 lobe) is another common alternative used in various applications. 

b) This screw features an extended cylindrical tip, known as a dog point, at the end of the threaded portion, enabling precise alignment and positioning in mating components.

Cross recee type H (phillips) is available upon request

Serretions under head / Extremely short length

Screw refer to ISO 14581

a) A ribbed neck screw is a type of fastener designed with a special feature on its shank or neck. Instead of a smooth or threaded surface, the neck of the screw has ribbed, serrated, or knurled features. These ribs or serrations provide additional grip and resistance when the screw is driven into a material, preventing it from rotating or loosening.