Countersunk vs. Wafer Head
Comparing 2 standards across 11 specifications. 11 key differences identified.
Flat Head (Countersunk / CSK, standardized under ISO 7046 and DIN 965) screws feature a flat top face and a conical tapered underside (90° in ISO Metric, 82° in US Imperial, 100° in Aerospace). Designed to seat inside a matching chamfered hole, the head sits 100% flush with or slightly below the surface of the joined material.
Wafer Head screws (Modified Truss / K-Lath / Framing Screws) feature an ultra-flat, razor-thin head with an integrated wide circular clamping rim and a flat underside. Engineered with a self-drilling TEK point or sharp piercing tip, they are standard in light-gauge steel stud framing, metal lath attachment, and drywall partition construction.
Specification Comparison Table
11 Parameters| Parameter / Spec | ||
|---|---|---|
|
Standard Specifications
|
ISO 7046 / DIN 965 / ASME B18.6.3 | ASTM C1002 (Steel studs) / ASTM C954 / DIN 7504-M |
|
Primary Applications
|
Woodworking, door hinges, machine slides, aircraft aerodynamic skin | Steel stud framing, stucco metal lath, HVAC ductwork, M.2 SSD hold-down screws |
|
Head Top Profile
|
100% Flat top face | — |
|
Countersink Angle (ISO Metric / DIN)
|
90 degrees | — |
|
Countersink Angle (US Imperial / ASME)
|
82 degrees | — |
|
Countersink Angle (Aerospace / NAS)
|
100 degrees (for thin structural aircraft skins) | — |
|
Length Measurement Rule
|
Overall Length (Measured from top of head to screw tip) | — |
|
Head Thickness
|
— | Ultra-thin low profile (~1.0 mm to 1.5 mm thick) |
|
Head Outer Diameter
|
— | Wide circular flange (10.0 mm to 11.5 mm on #8 screws) |
|
Point Types
|
— | Self-Drilling TEK Point (#2/#3 drill point) or Sharp Piercing Point (Type S) |
|
Common Drive Recess
|
— | Phillips #2 / Square #2 |