STAINLESS STEEL FLAT HEAD KNURLED INSERT NUTS

Flat Head Knurled Insert Nuts — A knurled insert nut - sometimes called a nutsert or rivet nut - adds a reusable internal machine thread to sheet metal or tube too thin to tap directly, letting a bolt be fitted and removed repeatedly rather than relying on a one-time rivet joint. It's set from one side with a nutsert tool that draws the body up, forming a clamping bulge on the blind side while the knurled outer surface bites into the hole wall to stop the insert spinning once a bolt is later torqued into it. The flat head sits proud of the surface on installation, which is fine for brackets, enclosures, and general sheet fixing where a raised head isn't a problem - where it would foul an adjoining surface or component, the countersunk version is the one to specify instead. Selecting the right insert means matching thread size to the bolt that will eventually be fitted, and confirming the drilled hole diameter against the insert manufacturer's specification for that size - too loose a hole and the knurl won't grip the wall properly, risking the insert spinning under torque rather than tightening down. Sheet or panel thickness also matters: the insert needs enough material thickness to form a solid blind-side bulge and resist pull-out under load. Grade selection should consider both the operating environment and the parent material: A2 stainless suits general indoor equipment and enclosures, while A4 is worth the extra cost for marine, washdown, or chemical-exposure settings where chloride attack would otherwise shorten service life. Where the insert is fitted into aluminium or a dissimilar metal panel, it's also worth checking for galvanic corrosion risk in damp conditions, since a stainless insert and an aluminium panel form a bimetallic couple that can corrode at the joint if moisture gets in and the metals aren't isolated.

FAQs
How does a nutsert differ from a rivet?
A rivet forms a permanent mechanical join between two parts with no thread; a nutsert creates a reusable internal thread, allowing a bolt to be fitted and removed repeatedly.

How does it differ from a half-hex insert nut?
Half-hex inserts use flat hex-shaped sections on part of the body instead of knurling to resist rotation; knurling relies on many small teeth gripping the hole wall, while half-hex relies on flat faces engaging the hole edge.

Does the parent panel thickness limit which insert can be used?
Yes - the panel needs to be thick enough for the blind-side bulge to form properly and resist pull-out; very thin sheet may need a longer-grip or different style insert, worth checking against the specific insert's rated material thickness range.