Screw - Screw Head Shapes

Screw Head Shapes

Pan head

A low disc with chamfered outer edge

Button or dome head

Cylindrical with a rounded top

Round head

A dome-shaped head used for decoration.

Mushroom or Truss head

Lower-profile dome designed to prevent tampering

Countersunk or flat head

Conical, with flat outer face and tapering inner face allowing it to sink into the material. The angle of the screw is measured as the full angle of the cone.

Oval or raised head

A decorative screw head with a countersunk bottom and rounded top. Also known as "raised countersunk" (UK)

Bugle head

Similar to countersunk, but there is a smooth progression from the shank to the angle of the head, similar to the bell of a bugle

Cheese head

Disc with cylindrical outer edge, height approximately half the head diameter

Fillister head

Cylindrical, but with a slightly convex top surface. Height to diameter ratio is larger than cheese head.

Flanged head

A flanged head can be any of the above head styles (except the countersunk styles) with the addition of an integrated flange at the base of the head. This eliminates the need for a flat washer.

Some varieties of screw are manufactured with a break-away head, which snaps off when adequate torque is applied. This prevents tampering and also provides an easily inspectable joint to guarantee proper assembly. An example of this is the shear bolts used on vehicle steering columns, to secure the ignition switch.