Truss Head vs. Wafer Head
Comparing 2 standards across 10 specifications. 10 key differences identified.
Truss Head screws (also known as Mushroom Head / Extra-Wide Pan) feature an extra-wide, low-profile domed head with a large-diameter flat bearing underside. Designed to span large clearance holes and clamp thin sheet metal without tearing or requiring external flat washers, they are widely used in metal building framing and cabinet door hardware.
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
10 Parameters| Parameter / Spec | ||
|---|---|---|
|
Standard Specifications
|
ASME B18.6.3 / IFI Standards | ASTM C1002 (Steel studs) / ASTM C954 / DIN 7504-M |
|
Primary Applications
|
Thin sheet metal ducting, electrical junction boxes, cabinet drawer slide tracks | Steel stud framing, stucco metal lath, HVAC ductwork, M.2 SSD hold-down screws |
|
Head Diameter Ratio
|
Extra-wide base (D_k ≈ 2.2× to 2.5× shank diameter) | — |
|
Head Height Profile
|
Ultra-low curved dome (flatter and wider than standard pan head) | — |
|
Bearing Surface
|
100% Flat horizontal bearing surface with maximum surface contact area | — |
|
Common Drive Recesses
|
Phillips (PH2), Square (Robertson #2), Combo, Slotted | — |
|
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 |