18-8 Stainless Steel Thinwall Ribbed Reduced Head Rivet Nuts

What are 18-8 stainless reduced head rivet nuts? These are blind threaded inserts in 18-8 stainless with a ribbed thinwall body and a reduced diameter head. They combine the corrosion resistance and load capacity of stainless with a head small enough to fit where a standard flat head will not. The ribs bite into the hole wall so the insert cannot spin when the bolt is torqued, which matters more with a reduced head because there is less friction under the head to help. AlbanyCountyFasteners.com stocks these from #8-32 through 5/16-18.

Thinwall Ribbed Reduced Head, Stainless Steel 18-8

Internal Thread:

#10-32

Why ribs matter more on a reduced head

Anti-rotation on a rivet nut comes from two places: the body gripping the hole wall, and the head clamping against the panel surface. A standard flat head contributes usefully to the second, since a wide face pressed hard against the panel generates real friction. Shrink that head and you lose part of that contribution, so more of the work falls on the body. That is why a reduced head insert with a smooth body is a poor combination and rarely offered, while reduced head with ribs is the standard pairing. The serrations cutting into the hole wall provide mechanical interlock that does not depend on head area at all.

Why choose 18-8 stainless reduced head rivet nuts

Smaller head fits tight clearances where a standard head will not
Substantially higher load capacity than aluminum at the same thread
Corrosion resistance for marine, washdown, and outdoor service
Ribs provide mechanical anti-rotation independent of head area
Thinwall body sets reliably in light sheet metal
Correct galvanic match for steel and stainless panels

Inch sizes and grip ranges

#8-32, 0.420 inch length, 0.020 to 0.080 inch grip
#10-32, 0.475 inch length, 0.020 to 0.130 inch grip
1/4-20, 0.580 inch length, 0.027 to 0.165 inch grip
5/16-18, 0.027 to 0.150 inch grip
Measure total panel thickness against the grip range before ordering

Common applications

Marine hardware in confined mounting locations
Trailer and transport equipment with closely spaced fixings
Steel chassis work in tight areas
Washdown and food equipment where clearance is limited
Outdoor machinery with compact mounting points
Retrofit work around existing components

Where bearing area matters more than clearance, flat head stainless ribbed rivet nuts spread load wider. On aluminum panels, aluminum reduced head inserts avoid a galvanic couple.

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18-8 Stainless Reduced Head Rivet Nut FAQs

Is #8-32 available only in reduced head?

In our current range, yes. The smaller thread sizes tend to be offered in reduced head because the applications calling for them are usually space constrained. For larger threads both head styles are stocked.

Will these pull through thin sheet?

More readily than a standard flat head, since the smaller head bears on less material. In very light or soft panel under repeated load, use the flat head version or add a backing washer.

Are these harder to set than aluminum?

Yes, stainless requires more pulling force throughout. At 5/16-18 a basic hand tool becomes hard work, so a ratcheting or pneudraulic tool is worth having for repeat installation.

Can I use these on an aluminum panel?

In dry indoor conditions yes, but where moisture is present the aluminum corrodes around each hole. For aluminum panels outdoors, use aluminum inserts instead.

What hole size do I drill?

The diameter specified for the insert. With a reduced head there is less material covered around the hole, so a ragged or oversize hole is both more visible and gives the ribs less clean wall to bite into.

Do reduced head inserts hold as much torque?

The ribs do most of the anti-rotation work, so torque resistance is comparable to a ribbed flat head insert. What you lose is some of the friction contribution from head clamping area.