Pan Head vs. Truss Head
Comparing 2 standards across 11 specifications. 11 key differences identified.
Pan Head screws (standardized under ISO 7045 and DIN 7985) feature a low-profile rounded top, vertical cylindrical outer sidewalls, and a flat horizontal bottom bearing surface. Providing clean aesthetics and strong clamping force without cutting into workpiece materials, it is the most common machine screw head in electronics and appliance assembly.
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.
Specification Comparison Table
11 Parameters| Parameter / Spec | ||
|---|---|---|
|
Standard Specifications
|
ISO 7045 / DIN 7985 / ASME B18.6.3 | ASME B18.6.3 / IFI Standards |
|
Primary Applications
|
Consumer electronics, sheet metal electrical enclosures, general machinery | Thin sheet metal ducting, electrical junction boxes, cabinet drawer slide tracks |
|
Head Top Geometry
|
Slightly domed / curved low-profile top surface | — |
|
Outer Edge Geometry
|
Vertical cylindrical sidewalls with smooth radiused top transition | — |
|
Bearing Surface Profile
|
100% Flat horizontal bearing surface | — |
|
Recess Recesses Supported
|
Phillips (PH), Pozidriv (PZ), Torx (TX), Slotted | — |
|
Countersinking Required
|
No (Mounts completely proud of the workpiece surface) | — |
|
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 |