|
SKETCH |
TITLE |
COMMENTS |
 |
COUNTERSUNK HEAD
(Flat) |
Most common usage is on
screw products where a flush fit is required on the surface, eg:
door hinges and timber joinery or into steel applications, eg:
manhole cover plates.
Can also be seen on bolt products, but usually accompanied by a
retention device such as a square or a lug as in plow and
earthmoving bolts. |
 |
RAISED COUNTERSUNK
(Oval & Instrument) |
Most often associated with
screw products in exposed applications.
Usually will be chrome or nickel plated for appearance and is
sometimes coupled with a cup washer to enhance the appearance,
eg: fittings on public transport. |
 |
PAN HEAD
(American Style) |
Predominantly used on screw
products where a flat bearing surface is required or conversely,
where a countersunk is not required.
More economically produced than countersunk. |
 |
PAN HEAD
(English Style) |
Now normally only found on
solid rivets and on some hot forged products. |
 |
ROUND HEAD
(Cup, Snap & Button) |
Declining popularity, but
does provide deeper slot capability than pan and therefore, is
more often used in woodscrews and machine screws.
When recessed with hex or x-recess becomes one form of button
head. |
 |
CHEESE HEAD |
Less popular than pan, but
again gives a deeper slot capability, so is most commonly seen
as a slot product on machine screws. |
 |
TRUSS HEAD
(Mushroom) |
Larger diameter and lower
profile head than round, pan or cup.
Is most commonly seen with slot or combination slot x-recess on
mush roofing bolt/nut product. |
 |
FILLISTER HEAD
(Raised Cheese) |
Rarely specified these days;
was formerly seen predominantly on machine screws. |
 |
WAFER HEAD |
Usually incorporating a
recess and most commonly found on self-drilling building
fasteners. |
 |
BUTTON HEADS |
Usually incorporating a
recess and most commonly found on self-tapping, self-drilling
screws and machine screws.
Sometimes incorporates a post to convert to a security or tamper
resistant recess. |
 |
BUGLE HEADS |
Most commonly found on
self-drilling screws used in plasterboard fixed to timber or
steel frames.
Designed to self-embed. |
 |
HEXAGON HEADS |
The most common head on bolt
products and also seen on many screw products. Can come in
several versions.
This one is referred to as full bearing face.
The manufacturer has the discretion to supply low tensile
products as full bearing face. |
 |
HEXAGON WASHER
FACED HEAD |
Hex washer faced is
specified for hexagon high tensile bolts and setscrews in the
Australian Standard - both unified and metric.
It is at the manufacturers option for other products; therefore,
it is not normally necessary to specify it except on specials.
Note: USA market refers to bolts and set screw products as cap
screws. |
 |
HEXAGON FLANGE HEAD
(Hex Washer Head) |
On bolts, correctly termed
hex flange head and when used on self-drilling screws, correctly
termed hex washer head.
Beware not to confuse with hex washer faced. |
 |
CUP SQUARE HEAD
(Coach Head) |
Normally referred to simply
as cup head, this standard product is predominantly used in
timber applications or very occasionally, in steel with a square
punched hole, eg: steel framed wheelbarrows. |
 |
CAP HEAD |
Normally incorporating a
recess and usually associated with very high tensile products,
eg: socket head cap screws. |
 |
DOMED HEXAGON HEAD
(Track Head) |
Sometimes found on special
bolts for engine heads, but more often on earthmoving equipment
as crawler track retaining bolts. |
 |
SQUARE HEAD |
Rarely seen now except on
some mining specials with very oversize square across flats.
Were used on timber bridgework and where larger bearing surface
was required.
Modern cold forming methods producing flange heads have hastened
its demise. |
 |
EXTERNAL TORX®
FLANGE |
Normally confined to special
high tensile products in high torque applications. |
 |
TEE HEAD |
Occasionally used as a bolt
head which is retained in a channel or where the space for a
head is restricted and narrow.
The head is usually, therefore, retained stationary and tension
is achieved by rotating the mating part, eg: a nut. |
