Countersunk Screws

Countersunk Screws for Trade and Industrial Applications in Australia

Countersunk screws have an angled (conical) head that sits flush with — or below — the surface of the material being fastened. They're the standard choice wherever a protruding head would be a hazard, obstruction, or cosmetic issue: structural joinery, panel fixing, machine guarding, and general fabrication across Australian trade and industry. AIMS Industrial stocks countersunk screws from Champion, Hobson, and Bremick in a range of drive types, materials, and thread forms.

Drive types stocked

• Socket (hex key / Allen) drive — the trade standard for high-torque applications; ISO 10642 (socket countersunk head cap screw). Better resistance to cam-out than Phillips or Pozi; requires the correct hex key or bit
• Phillips drive — widely used in general fastening, joinery, and light fabrication; compatible with most impact drivers and screwdrivers
• Pozi (Pozidrive) — improved cam-out resistance over standard Phillips; visually similar but the cross angle is different — use a Pozi bit, not a Phillips, to avoid stripping

Materials and finishes

• Stainless steel (A2/A4) — for outdoor, marine, food, and corrosive environments; A4 for severe marine or chemical exposure
• Zinc-plated steel — for internal and sheltered applications where corrosion isn't a primary concern
• High-tensile (Grade 8.8/12.9) — for structural and mechanical applications requiring higher clamping force

Metric thread sizing

Countersunk screws are sized by diameter (M3 through M20 in common stock), pitch (coarse and fine thread), and length (measured from the top of the head for countersunk, since the head sits flush). Always specify all three dimensions — diameter, pitch, and length — when ordering.

Countersinking practice

For a flush fit, the countersink angle in the workpiece must match the screw head angle (typically 90° for metric socket countersunk screws). Use a countersink bit matched to the screw angle; an incorrect angle leaves either a gap around the head or prevents the head from seating fully. In softer materials, the screw head will self-countersink slightly under torque — in harder materials, always pre-countersink.

Related products

See also: socket head cap screws (parallel head for socket drive), grub screws (set screws), and hex bolts and nuts.

For specific grades, thread forms, or volume requirements, contact our team.