Pay Attention ToFIXTURE TYPE
– Some fixtures are not suitable for countersunk heads, because of the risk of pulling heads through. For example, thin sheet metal.
– If countersunk heads are used with solid material, they need pre-drilled phases / countersunk holes.REQUIRED SURFACE
– Countersunk heads leave a flat and smooth surface after installation.
– Round Top, Hex and other similar heads stay on top of surface and are visible to the eye.HEAD SIZE
– Countersunk heads are smaller and they are easier to pull through fixed material. It is important in load-bearing connections.
– Large bearing surface provides better holding strength.DESIGN
– Countersunk heads are less visible to the eye than other heads.
Most Common Head Styles
Rounded Top HeadsUsed, when flat surface is not required after installation Internally driven Typically used with solid materials, such as metal
The oldest design
Becoming less common
Less rounded than Round Head
More rounded than Pan Head and less rounded than Rounded Read
Provides large bearing surface with low profileGood holding strength
Modified Truss Head
Provides extra large bearing surface with low profileBetter holding strength than Truss Head
Countersunk HeadsUsed, when flat, smooth surface is required after installation Internally driven Typically used with soft materials, such as wood For solid material such as metal, needs pre-drilled phases / countersunk holes.
Common on wood screws
Primarily used in drywall and wood decing
Design includes a decorative rounded top
Common on wood screws Nibs under head allow screw to countersink better for a smooth finish
Hex heads are driven with the driver’s force against outside of the head
Common in bolts
Allow high torque
Square heads are driven with the driver’s force against outside of the head
Heads are often installed flush with surrounding materials
Needs counterbored holes when installed flush with surrounding