|Description||Application & Advantages|
|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 surface, cylindrical sides and a flat bearing surface.
|Has a general purpose bearing area. Can be substituted in most applications for round, truss or binding heads.|
|Binding||Has a rounded top surface and slightly tapered sides. The bearing surface is flat with the slotted variety having an annular undercut adjacent to the shank.||Preferred design for making a firm electrical connection.|
|Flat 82°||A countersunk head with a flat top surface and a cone-shaped bearing surface with a head angle of approximately 82°.||Used in applications where protrusion of the fastener above the mating sufrace is unaccepttable. Use a protrusion gage when measuring head height.|
|Similar to an 82° flat head except that the head is undercut to 70% of its normal side height.||Standard for short lengths because it allows greater length of threads. Also avoids transition fillet and assembly interference.|
|Flat 100°||A countersunk head with a flat top surface and a cone-shaped bearing surface with a head angle of approximately 100°.||Preferred over an 82° flat head when fastening in soft materials. The 100° countersunk head distributes pressure over a larger surface area.|
|Fillister||Has a rounded top surfave, cylindrical sides, and a flat bearing surface. The greater side height is what distinguishes a fillister head from a pan head.||Preferred style for use in counterbored holes.|
|Has an indented top surface, six flat sides, and a flat bearing surface.||Preferred in high volume assembly where pneumatic equipment is used to drive the screw. Can transmit significantly higher tightening torque levels than other head styles.|
|Has an indented top surface, six flat sides with a flat washer which projects beyond the sides and provides a flat bearing surface. The washer and hex are formed together as one piece.||Offers greater protection to the mating surface than a standard indented hex head. Increased bearing surface reduces likelihood of crushing mating surfaces.|
|Truss||Has a low rounded top with a flat bearing surface greater in area than a round head screw of the same nominal size.||Weaker than pan or round heads but preferred in applications where minimal clearance exists above the head. Truss profile provides a trim finished assembly appearance.|
|Oval||A countersunk head with a rounded top surface and a cone-shaped bearing surface of approximately 82°.||Preferred over a flat head in conical applications, or when a more decorative finished look is desired. The countersunk surface nests into mating countersunk application sites.|
|Similar to an 82° oval head except that the head is undercut to 70% of its normal side height.||Standard for short lengths because it allows greater thread length.|
|Round||Has a semi-eliptical top surface and a flat bearing surface||Sometimes preferred over pan head for its smooth surface and appearance.|
Smith Fastener Company, A California Corporation - 8181 State Street, South Gate, California 90280 - Phone: ( 323 ) 587-0382 - FAX: ( 323 ) 587-8712 - E-mail: [email protected] - Copyright © 2000 by Smith Fastener Company - Last updated: May 22nd, 2006 - http://www.smithfast.com/msheadstyles.htm