|
Schematic |
Head
Style |
Description |
|
 |
Pan |
Slotted pan heads have a flat or gently rounded
top surface, cylindrical sides and a flat
bearing surface. Phillips and Torx pan
heads have a rounded top, cylindrical sides and
a flat bearing surface. |
|
 |
Binding
Undercut |
Has a rounded
top surface and slightly tapered sides.
The bearing surface is flat with an annular
undercut adjacent to the shank. |
|
 |
 |
A countersunk
head with a flat top surface and a cone-shaped
bearing surface with a head angle of
approximately 82 degrees. |
|
 |
Flat
Undercut |
Similar to an 82
degree flat head except that the head is
undercut to 70% of its normal side height. |
|
 |
 |
A countersunk
head with a flat top surface and a cone-shaped
bearing surface with a head angle of
approximately 100 degrees. |
|
 |
Fillister |
Has a rounded top surface, cylindrical sides,
and a flat bearing surface. The greater
side height is what distinguishes a fillister
head from a pan head. |
|
 |
Indented
Hex |
Has an indented top surface, six flat sides, and
a flat bearing surface. |
|
 |
Indented
Hex Washer |
Has an indented top surface, six flat sides and
a flat washer which projects beyond the sides
and provides a flat bearing surface. The
washer and hex head are formed together as one
piece. |
|
 |
Truss |
Has a low rounded top surface with a flat
bearing surface greater in area than a
round-head screw of the same nominal size. |
|
 |
Oval |
A countersunk
head with a rounded top surface and a
cone-shaped bearing surface of approximately 82
degrees. |
|
 |
Round |
Has a semi-elliptical top surface and a flat
bearing surface. |
