Flat Head Round Body Rivet Nuts

What are flat head round body rivet nuts? These are smooth bodied rivet nuts with a large flat head that sits on the panel surface, spreading the clamping load across a wide bearing area. The flat head is the most common rivet nut head style because it does two things well: it gives the mounted component a flat, consistent face to seat against, and it stops the insert pulling through thin or soft material under load. Combined with a thickwall smooth body, it suits general purpose work in a plain drilled hole. AlbanyCountyFasteners.com stocks these in aluminum, in 1/4-20 and 5/16-18.

Flat Head

Thickwall Smooth Large Head, Aluminum

Why the head style matters as much as the body

The body controls how the insert holds in the hole. The head controls how the panel behaves around it. A large flat head spreads the load of the mounted part across a broad ring of material, which is what stops a rivet nut slowly pulling through sheet metal under a bolt torqued repeatedly over years. It also gives you a flat, predictable mounting face, which matters when the component bolting down needs to sit square. What you give up is profile: the head stands proud of the panel by its own thickness, so on a surface where nothing should protrude, a reduced or countersunk head is the better answer.

Why choose flat head rivet nuts

Wide bearing area spreads load and resists pull-through in thin panel
Flat, consistent mounting face for the component being attached
Most widely used head style, so sizing and tooling are straightforward
Thickwall smooth body gives strength and grip in a plain drilled hole
Aluminum construction suits aluminum panels without a galvanic couple

Sizes stocked

1/4-20 at 0.625 inch length, 0.020 to 0.080 inch grip range
5/16-18 at 0.750 inch length, 0.030 to 0.125 inch grip range
Both in thickwall smooth aluminum with a large flat head
Measure your panel thickness against the grip range before ordering

Common applications

Aluminum panels, enclosures, and equipment housings
Trailer and RV fixture mounting
Automotive and truck accessory brackets
Sheet metal assemblies where the head can sit proud
Retrofit work using existing drilled holes
Joints where the mounted part needs a flat seating face

Where a lower profile is needed, see the reduced head low profile options. For higher torque resistance in the same size range, ribbed rivet nuts bite into the hole wall.

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Flat Head Rivet Nut FAQs

How far does the head stand proud?

By its own thickness, which is typically a small fraction of an inch. Enough to see and feel, and enough to matter if a flat panel has to slide across it. For a lower profile, use a reduced head insert.

Can I countersink for a flat head?

Not usually with this style, since the underside of the head is flat rather than tapered. Counterboring the hole to the head diameter can work in thicker material, but it removes material from an already thin panel and is rarely worth it.

What grip range do I need?

Measure the total thickness of the panel the insert is going through. The grip range printed on the insert tells you what it can clamp. Outside that range the body will not form a proper bulge behind the panel.

Why aluminum rather than steel?

For aluminum panels, matching the material avoids galvanic corrosion around every hole. Aluminum is also lighter and easier to set, though it carries less load than stainless. For steel panels or higher strength requirements, choose a stainless insert.

What tool do I need?

A rivet nut tool with a mandrel matched to the thread size. 1/4-20 and 5/16-18 are both settable with a good hand tool, though a ratcheting or pneudraulic tool makes repeat installation much easier.

Will these work in plastic or composite?

They can, with care. The wide head helps spread load, but soft materials may deform as the body collapses. Test in scrap first, and consider a well nut if the material is fragile or the joint needs sealing.