| SLOT |
PHILLIPS |
SLOTTED
PHILLIPS
COMBO |
SQUARE |
PHILLIPS
SQUARE
COMBO |
PHILLIPS
HEX
HEAD |
SLOTTED
HEX |
SIX
LOBE |
|
| TYPES
OF BOLT AND SCREW HEADS |
 |
PAN
HEAD: Recommended for new designs to replace round, truss and
binding heads. Provides a low large diameter head, but with characteristically
high outer edge along the outer periphery of the head where drive
action is most effective for high tightening torques. Slightly different
head contour where supplied with recessed head. See dotted line. |
 |
ROUND
HEAD: Not recommended for new design (see pan head). This head
was the most universally used design in the past for industrial bolts or screws. |
 |
FILLISTER
HEAD: The standard oval fillister head has a smaller diameter
than the round head, but is higher with a correspondingly deeper slot.
The small diameter head increases the pressure applied on the smaller
area and can be assembled close to flanges and raised surfaces |
 |
BINDING
HEAD (Straight Side): Most generally used in electrical and radio
work because of its identifying undercut beneath the head, which binds
and eliminates fraying of stranded wire. A medium - low head with
ordinarily sufficient bearing surface. Not recommended as a Phillips
Recessed head – see Pan Head for better functional design. |
 |
TRUSS
HEAD: Also known as oven head, stove head, and oval binding head machine screws.
A low, large diameter head that can be used to cover larger diameter
clearance holes in sheet metal when additional play in assembly tolerance
is required. |
 |
ONE
- WAY HEAD: This tamper-proof type of head, once assembled cannot
be removed, yet is driven with a standard screwdriver. |
 |
FLAT
AND OVAL HEADS (UNDERCUT): The standard flat or oval head 80°
to 82° counter sunk machine screw will fit a standard counterbored hole
and is particularly adaptable to flush assemblies in thin stock. |
 |
SQUARE
SHOULDER SCREWS: An adaptation of the standard carriage bolt design.
Possesses a truss head on a square shank, which resists rotation when
located or driven into place. |
 |
INDENTED
HEXAGON: A wrench head industrial fastener made to standard hexagon head
dimensions. The hex possesses an identifying depression in the top
surface of the head. |
 |
INDENTED
HEXAGON WASHER HEAD: The same as the standard indented hexagon
head but with a washer section at the base of the head to protect
the finish of the assembly from wrench disfigurement, and to economically
replace a separate bolt & washer assembly. |
 |
HEXAGON
HEAD (TRIMMED): This is the standard type of wrench - applied
hexagon head, characterized by clean, sharp corners trimmed to close
tolerances. Recommended for general commercial applications. |
 |
HEX
FLANGE: Similar to hex washer with the exception that the top
of the washer-flange shall be conical or slightly rounded within the
periphery of the flange diameter. The contour of the flange edges
shall be optional provided minimum flange thickness is maintained. |
