Head Styles for Self Tapping Screws

Schematic Head
Style
Description Application & Advantages
Link to Bugle Head specs Bugle A countersunk head with a flat top and a concave underhead bearing surface. Designed specifically fo use in drywall. Distributes bearing stress over a wider area than flat heads.
Link to Pan Head specs Pan Slotted pan heads have a flat or gently rounded top surface, cylindrical sides and a flat bearing surface.
Phillips, Torx® and square pan heads have a rounded top surface, cylindrical sides and a flat bearing surface.
For general applications. Can be substituted in most applications for round, truss or binding heads.
Link to Flat 82 degree Head 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.
Link to Flat Undercut Head Flat
Undercut
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.
Link to Indented Hex Head Indented
Hex
Has an indented top surface, six flat sides, and a flat bearing surface. Preferred in high volume assembly where pneumatic equipment is uded to drive the screw. Can transmit significantly higher tightening torque levels than other head styles.
Link to Indented Hex Washer Head Indented
Hex Washer
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. Increased bearing surface reduces likelihood of crushing mating surfaces.
Serrated Hex Washer Head image Serrated
Hex Washer
Same as an indented Hex Washer Head but with serrations formed into the bearing surface on the underside of the washer. Serration geometry is oriented to resist loosening. Also slows the screw at the point of engagement with the mating piece of sheet metal so as to minimize stripping.
Link to Truss Heads Truss Has a 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 appearance.
Link to Wafer Head specs Wafer A countersunk head with a flat top surface and a cone-shaped bearing surface. The wafer's 70° conical underhead area does not extend to the outer edge of the head, providing a bearing surface of 16° aroung the circumference of the underhead. Preferred head style for Type-CSD self drilling screws. Provides the necessary bearing surface and flush fit in wood and softer materials. The head/shank fillet is contoured to strengthen the underhead area.
Link to Oval Head Specs Oval A countersunk head with a rounded top surface and a cone-shaped bearing surface of approximately 83°. 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.
Link to Oval Undercut Head specs Oval
Undercut
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.
Link to Round U Drive Screws Round
(U-drive)
Has a semi-elliptical top surface and a flat bearing surface. Standard head style for drive screws. Provides efficient non-torque fastening for high-speed assembly.

See also: Self-Tapping Drive Types



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Phone: ( 323 ) 587-0382 • FAX: ( 323 ) 587-8712 • E-mail: [email protected]
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