Socket Head Cap vs. Truss Head
Comparing 2 standards across 11 specifications. 11 key differences identified.
Socket Head Cap Screws (SHCS, standardized under DIN 912 and ISO 4762) feature a compact cylindrical head whose height is approximately equal to the screw shank diameter, housing a deep internal hexagonal (Allen) or Torx socket. Engineered for high-tensile alloy steel applications, it allows high-torque fastening inside tight, counterbored machine recesses.
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 4762 / DIN 912 / ASME B18.3 | ASME B18.6.3 / IFI Standards |
|
Primary Applications
|
Industrial tooling, machine tools, 3D printer extruders, automotive cylinder heads | Thin sheet metal ducting, electrical junction boxes, cabinet drawer slide tracks |
|
Head Geometry
|
Tall cylindrical head with knurled or smooth outer diameter | — |
|
Head Height Ratio
|
Head Height ≈ Screw Major Diameter (H ≈ D) | — |
|
Head Outer Diameter Ratio
|
Head Diameter ≈ 1.5 × Screw Diameter (D_k ≈ 1.5D) | — |
|
Recessed Drive Type
|
Internal Hexagon (Allen) or Hexalobular (Torx) | — |
|
Standard Steel Property Class
|
High-tensile Class 12.9 (1,220 MPa) / Class 10.9 / Class 8.8 / A2-70 Stainless | — |
|
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 |