Steel Dome Head Tri-Fold Rivets

When do I need steel instead of aluminum tri-fold rivets?

Two situations. The obvious one is panel material: riveting steel skin with an aluminum rivet puts the aluminum at the bottom of the galvanic pairing, so in road spray or weather the rivet itself corrodes away rather than the panel. Match steel to steel and that problem disappears. The less obvious one is load. Tri-fold rivets are non-structural by classification, but that does not mean lightly loaded, and a heavy truck body panel taking constant road vibration asks more of a fastener than a sheet metal enclosure does. Steel gives substantially more shear and tensile capacity than aluminum at the same diameter, which buys margin in the joints that work hardest.

Why choose steel dome head tri-fold rivets

• Considerably higher shear and tensile strength than aluminum tri-fold rivets
• Correct galvanic match for steel panels and steel framing
• Three folding legs spread load for a wide blind side clamp
• Sealing washer under the head for a weather resistant joint
• Holds well in elongated and oversized holes from previous fasteners

Sizes and grip ranges

• 1/4 inch body, in four grip ranges covering 0.250 through 0.625 inch
• Order by body diameter, then match grip range to your total material stack
• Include the sealing washer thickness in the grip calculation
• For 3/16 inch tri-fold work, our aluminum versions cover that diameter

Common applications

• Steel truck body and trailer panels
• Metal building siding and roofing on steel framing
• Heavy duty repair where load and vibration are significant
• Steel sheet where a standard rivet would pull through
• Repairs over holes enlarged by previous fasteners
• Exterior steel panel joints where the sealing washer adds protection

On aluminum panels, use aluminum dome head tri-fold rivets instead to avoid a galvanic couple. Background on the folding action and where tri-fold rivets fit is on our tri-fold rivets page.

Related Categories

• Dome Head Tri-Fold Rivets
• Aluminum Dome Head Tri-Fold Rivets
• Tri-Fold Rivets
• Structural Rivets
• Rivet Tools

Steel Dome Head Tri-Fold Rivet FAQs

Will these rust?

Bare steel corrodes wherever moisture reaches it. The sealing washer protects the joint under the head, which helps considerably on an exterior panel, but the mandrel break remains exposed. For long term outdoor service on a visible surface, consider whether a stainless option elsewhere in the range suits your application better.

How much stronger are these than aluminum?

Substantially, in both shear and tensile. Steel with a steel mandrel considerably outperforms aluminum with an aluminum mandrel at the same diameter, which is why it is the choice for heavier duty repair.

Can I use them on aluminum panels?

Not where moisture is present. Steel against aluminum makes the aluminum sacrificial, so the skin corrodes around every rivet until the holes enlarge. Use aluminum tri-fold rivets for aluminum work.

Why only 1/4 inch?

That is the diameter where steel tri-fold rivets see the most demand, since it covers heavy truck and trailer body work. Our aluminum tri-fold range covers 3/16 inch and smaller for lighter panel applications.

Do they need a stronger tool?

More force than aluminum, and 1/4 inch is a large diameter, so a lever or pneumatic tool is worth using. A hand riveter will set them but the effort adds up quickly over a panel.

Are these structural rivets?

No. Tri-fold rivets are classified non-structural regardless of material, since the mandrel is not mechanically locked. For structural shear and vibration resistance, use structural blind rivets.