Machine screws, Slotted flat head; Material. Stainless steel 18-8. A corrosion resistant steel alloy. The most common stainless steel for general hardware use. Zinc plated steel. A low carbon steel for general use. Zinc plated for moderate corrosion resistance. This is a scew head with a tall domed head. It has a head whose diameter is less than the pan head. It is usually used as wood screws and machine screws. This screw drive has a slightly rounded head with short vertical sides. It is mostly substituted in applications requiring round, truss or binding heads. Oval Head/Raised Countersunk.
| 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. |
Slotting Machine Tools
Used Screw Head Slotting Machinery
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