|
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. |
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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. 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. |
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FLAT
AND OVAL HEADS (UNDERCUT): The standard flat or oval head
80° to 82° counter sunk screw will fit a standard counterbored
hole and is particularly adaptable to flush assemblies in thin
stock. |
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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. |
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INDENTED
HEXAGON: A wrench head fastener made to standard hexagon
head dimensions. The hex possesses an identifying depression
in the top surface of the head. |
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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. |
