Rivet Nut vs Plus Nut vs Jack Nut vs Well Nut vs PEM Nut vs Weld Nut
When you need a permanent threaded socket in sheet metal, a panel, or a tube, you have six common options: rivet nuts (rivnuts, nutserts), plus nuts, jack nuts, well nuts, PEM nuts (press-in nuts), and weld nuts. Each works differently and is right for a different situation. This guide explains how each one works, when to choose it, and when to choose a different fastener instead.
Rivet Nut (Rivnut, Nutsert, Threaded Insert)
How it works: A rivet nut is a hollow, threaded fastener with a knurled body and a flange head. You drill a round hole in the panel, insert the rivet nut, and set it with an installation tool. The body collapses against the back side of the panel (or swages outward against the hole wall, in the ISR series), creating a permanent threaded socket installable from one side only.
- Best for: sheet metal and panel applications where you can drill a clean round hole and need a strong, repeatable threaded socket. Permanent installation.
- Materials available: steel zinc plated, aluminum, 18-8 stainless steel
- Sizes: #4-40 through 1/2-13 inch, M4 through M12 metric
- Tool required: rivet nut installation tool (hand or powered)
- Strengths: highest pull-out strength of the blind fasteners; reusable threads; works in a wide range of panel thicknesses; broadly stocked
- Weaknesses: requires a clean drilled hole; can spin if hole is oversized; needs a dedicated installation tool
Shop rivet nuts at Eugene Fastener »
Plus Nut
How it works: A plus nut is a variant of the rivet nut with a cross-shaped (plus-sign) body that expands as the fastener is set. The four expanding legs grip the panel in four points instead of compressing radially like a standard rivet nut. The cross design gives more grip in soft or thin materials where a standard rivet nut might not seat firmly.
- Best for: thin or soft materials (sheet aluminum, fiberglass, thin steel) where a standard rivet nut would not grip securely. Common in automotive trim and aerospace panels.
- Materials: typically aluminum or steel
- Tool required: standard rivet nut installation tool
- Strengths: better hold in thin/soft material than standard rivet nut; same installation method (no special tool)
- Weaknesses: lower pull-out strength than a properly-installed standard rivet nut in proper-thickness material; slightly more expensive
Choose plus nut over rivet nut when: the panel is too thin or too soft for a standard rivet nut to grip reliably.
Jack Nut
How it works: A jack nut is a plastic-bodied insert with a metal threaded core. You push it through a hole, then turn a screw into it. As the screw turns, the plastic body distorts outward to grip the back side of the panel.
- Best for: very thin materials (sheetrock, plastic, foam-core panels), one-time installations, and applications where weight matters and load is light.
- Materials: nylon body with steel or brass threaded insert
- Tool required: just a screwdriver — no special installation tool
- Strengths: no special tool needed; works in materials too thin or soft for rivet nuts; very low cost per piece
- Weaknesses: much lower pull-out strength than rivet nuts; not suitable for high-load or high-torque applications; threads are typically not reusable many times
Choose jack nut over rivet nut when: you don’t have an installation tool, the panel is too thin/soft for a rivet nut, or load requirements are very low.
Eugene Fastener stocks a selection of jack nuts — browse our R-Nuts category for available sizes.
Well Nut
How it works: A well nut is a rubber- or neoprene-bodied insert with a threaded brass insert at the bottom. You push it through a hole and tighten a screw into it. As the screw tightens, the rubber body compresses and bulges outward, sealing the hole and gripping both sides of the panel.
- Best for: sealing applications (where you don’t want water or air leakage through the fastener hole), vibration-damping applications, and panels where the rubber body provides electrical insulation.
- Materials: neoprene or EPDM rubber body, brass threaded insert
- Tool required: just a screwdriver
- Strengths: waterproof seal; absorbs vibration; protects panel from direct metal-to-metal contact; no installation tool
- Weaknesses: very low pull-out strength compared to rivet nuts; not suitable for high-load applications; threads degrade over time and with sun exposure
Choose well nut over rivet nut when: you need a watertight seal, vibration isolation, or electrical isolation through the fastener.
Eugene Fastener stocks well nuts — browse our R-Nuts category for available thread sizes.
PEM Nut (Press-In / Self-Clinching Nut)
How it works: A PEM nut (also called a press-in or self-clinching nut) is installed by pressing the fastener into a hole in the panel using a hydraulic or arbor press. The nut’s knurled or hexagonal flange displaces the panel material into a groove, locking the nut in place permanently. PEM nuts are extremely strong but require press equipment to install.
- Best for: high-volume sheet metal fabrication where press equipment is already in the workflow. Common in electronics enclosures, server racks, and structural sheet metal assemblies.
- Materials: steel (zinc plated, stainless), aluminum
- Tool required: hydraulic press, arbor press, or fastener insertion press
- Strengths: highest pull-out and torque-out strength of any blind fastener; permanent, can’t back out; very fast installation in production
- Weaknesses: requires expensive press equipment; access to both sides of panel needed during installation; not field-installable; doesn’t work in panels too hard to displace (hardened steel, thick plate)
Choose PEM nut over rivet nut when: you have press equipment in your production line and need maximum strength. Don’t choose PEM nuts for one-off jobs, field repairs, or installations without press access.
Eugene Fastener stocks PEM nuts and similar press-in fasteners — contact sales for availability.
Weld Nut
How it works: A weld nut is welded permanently to the back side of the panel using resistance welding (typically projection welding). The nut has small projections that melt and bond to the panel under welding current and pressure.
- Best for: permanent assemblies in steel where you have welding capability and access to the back side of the panel. Common in automotive bodies, structural steel, appliance manufacturing.
- Materials: steel (zinc plated, stainless variants), in many head styles (hex, square, round, tab)
- Tool required: resistance welding equipment
- Strengths: strongest possible threaded socket connection; permanent; very low cost per piece in volume; corrosion-resistant if matched material
- Weaknesses: requires welding equipment and skill; back-side access required; not suitable for thin/soft materials; weld marks visible on the panel
Choose weld nut over rivet nut when: you have welding equipment, full back-side access, and need the absolute strongest threaded connection. Most common in automotive body assembly.
Shop weld nuts at Eugene Fastener »
Quick Decision Matrix — Which Fastener for Which Job?
| If you need… | Choose |
|---|---|
| A strong threaded socket in standard sheet metal, installed from one side | Rivet Nut (IKF series) |
| A threaded socket in a blind hole or unknown panel thickness | Rivet Nut (ISR series) |
| A threaded socket in very thin or soft material (where rivet nut won’t grip) | Plus Nut |
| A low-cost threaded mount with no special tool, light load only | Jack Nut |
| A waterproof or vibration-isolating threaded fastener | Well Nut |
| Maximum strength in production sheet metal with press equipment | PEM Nut |
| Permanent strongest connection with welding capability | Weld Nut |
For most sheet metal, panel, and tubing applications where you need installable-from-one-side threads and have a drill, the rivet nut is the right choice. Choose IKF (fixed grip) when you know your panel thickness; choose ISR (unlimited grip) when you don’t. The other fastener types are specialized solutions for specific situations.
Frequently Asked Questions
Are rivet nuts and rivnuts the same thing?
Yes. “Rivnut” is a brand name (originally from Bollhoff) that became a generic term. Rivet nut, rivnut, nutsert (Avdel/Stanley brand), and threaded insert all refer to the same product family. Eugene Fastener stocks RivetKing IKF and ISR series rivet nuts.
Which fastener is strongest?
In ascending order of strength: well nut (lowest) → jack nut → plus nut → rivet nut → weld nut → PEM nut (highest). Rivet nuts cover the vast majority of applications because they offer high strength without requiring welding or pressing equipment.
Can I substitute one for another?
Generally no. Each fastener is designed for a specific installation method and panel condition. Substituting (for example) a jack nut for a rivet nut in a high-load application will likely result in failure. Pick the fastener that matches your installation method and load requirement.
Do rivet nuts and PEM nuts use the same hole size?
No. PEM nuts require a smaller hole than rivet nuts of the same thread size, because the PEM nut displaces the panel material to lock in. Always follow the manufacturer’s specified hole size for the fastener you’re using.
Can I use a rivet nut for a wood panel?
Rivet nuts are designed for sheet metal, plastic, fiberglass, and other rigid materials that compress predictably. Wood is generally too soft and the grain causes uneven gripping. For wood panels, use a threaded insert designed for wood (e.g., E-Z LOK, threaded insert with screw-in or hammer-in installation) instead of a rivet nut.
Related Resources
- Rivet Nut Selection Guide — choosing IKF vs ISR, materials, sizes, and grip ranges
- Rivet Nut Drill Bit & Hole Size Chart — matched drill bits for every rivet nut size
- Rivet Nut Tool Selection Guide — choosing your installation tool
- How to Install a Rivet Nut — step-by-step installation walkthrough
- Shop Rivet Nuts (IKF & ISR)
- Shop Weld Nuts