Aircraft Screws

   Machine screws

Materials available include Steel, Stainless steel and Brass.

Countersunk machine screw (Measure: total length).
A Countersunk machine screws is designed to fit flush with the surface of the fastened material for a smooth safe finish.  

Raised Countersunk machine screw.
A raised head on a countersunk machine screw giving a slightly rounded top for a more finished look.

Pan head machine screw (Measure: from under head). A domed head machine screw sits on the surface of the material to be fastened, has a flat underside and can be used with washers.

Cheese Head machine Screw (Measure: from under head). Head style: Slotted. A Cheese head machine screw sits on the surface of the material to be fastened and have a flat underside, can be used with washers.
 
Round Head machine screw (Measure: from under head). Head style: Slotted. A Round head machine screw sits on the surface of the material to be fastened and have a flat underside, can be used with washers.
Shapes of screw head

(a)pan      (b)button     (c)round    (d)truss    (e)flat        (f)oval

Pan head: a low disc with chamfered outer edge.
 
Button or dome head: cylindrical with a rounded top.
 
Round: dome-shaped, commonly used for machine screws.
 
Truss: lower-profile dome designed to prevent tampering.
 
Flat or Countersunk: conical, with flat outer face and tapering inner face allowing
it to sink into the material, very common for wood screws.
 
Oval: countersunk with a rounded top.
 
Cheese head: disc with cylindrical outer edge, height approximately half the
head diameter.
 
Fillister head: cylindrical, but with a slightly convex top surface.
 
Socket head: cylindrical, relatively high, with different types of sockets (hex,
square Torx, etc.)
 
Mirror screw head: countersunk head with a tapped hole to receive a separate
screw-in chrome-plated cover, used for attaching mirrors.
 
N.B: Headless machine screws, called "setscrews" or "grub screws", are also used. They
either have a socket or a slot.