Rivets and Fastening Pins

A rivet makes a permanent joint where welding isn’t practical and screws would shake loose. Rivet tools and fastening pins create permanent, shake-proof joints where welding is impractical or access is restricted. For anyone joining sheet metal, ductwork, gutters, trailer panels, or roofing — the right pick comes down to three things: the rivet type, the grip range matched to material thickness, and the rivet material matched to what it’s going into. Get those wrong and you’ve got galvanic corrosion, weak joints, and rework.

The single most important access question first. Blind (pop) rivets are installed from one side, while solid or pin-style fasteners require access to both sides. Most building and fab work uses blind rivets for exactly that reason — one operator, one side, done.

One honest limitation up front. Rivets should not be used in thick materials or in tensile applications, as their tensile strengths are quite low relative to their shear strengths. Rivets are shear fasteners. Pull straight out on them and they’re weak. Load them sideways and they hold.

Rivet Types and What Each One Solves

Blind rivets sort into six common types, and each one fixes a specific problem. Battery rivet gun rivets come in six main types, each designed for specific applications and material conditions. Choosing the correct type affects both installation success and joint strength.

Type	Best for	Key feature	Grip range
Standard	Consistent material thickness, general purpose	Most economical	0–6mm typical
Multigrip	Varying thickness, blind holes	One rivet grips a range of thicknesses	0–10mm typical
Structural	High-strength, load-bearing	Maximum shear and tensile strength	0–6mm typical
Trifold	Soft or brittle materials (fiberglass)	Folds instead of expanding to prevent cracking	0–10mm
Unigrip	Wide grip range work	One size handles multiple thicknesses	0–12mm
Monohuck	Heavy-duty lockbolt-style	Maximum structural strength	0–6mm

Standard rivets are the workhorse. Standard rivets work well when material thickness remains consistent across your project. They’re the most affordable option and perform reliably in automotive fabrication, HVAC ductwork, and structural applications.

Multigrip and unigrip earn their keep when thickness varies. Multigrip rivets excel when material thickness varies or when you’re working with assemblies of different thicknesses. Their extended grip range means fewer different rivet sizes to stock and faster work without constant size changes. Same idea on the steel side: the Uni-grip blind rivet solves issues for workshops facing varied thicknesses. Its broad grip range means one size can replace three standard rivets, which reduces stock issues.

When the joint actually carries load, step up. Structural rivets deliver significantly higher shear and tensile strength compared to standard rivets. The reason they’re stronger: they are designed to create a mechanical interlock, where the mandrel stays within the rivet post-installation to increase shear strength.

For the heaviest joints, monohuck lockbolt styles top the list. Monohucks provide lockbolt-style strength in a blind fastener format. They’re ideal for heavy-duty applications requiring maximum joint strength. Trifold rivets handle the opposite problem — fragile material. Trifold rivets solve the problem of installing fasteners in soft or brittle materials that crack under standard rivet expansion. The folding action distributes stress more gently.

Western Building Center carries steel fastening pins in several lengths — 1-1/4”, 2”, 2-1/2”, and 3” — sold in 100-packs for pin-style fastening work.

Sizing: Diameter and Grip Range

Mis-sizing is the most common mistake at the counter. Select a rivet diameter and length that matches your material thickness and grip range. Two numbers matter: the diameter (how big the hole) and the grip range (the stack of material the rivet can clamp).

Here’s a real spread of common diameters and grip ranges for aluminum/steel blind rivets:

Rivet size	Diameter	Grip range	Drill bit
3.2 × 8.0	3.2mm	0.5–5.0mm	3.3mm
4.0 × 10.0	4.0mm	0.5–6.5mm	4.1mm
4.8 × 10.0	4.8mm	0.5–6.5mm	4.9mm
4.8 × 25.0	4.8mm	11.0–15.5mm	4.9mm
6.5 × 20.0	6.4mm	6.0–14.0mm	6.5mm

Notice the same 4.8mm diameter covers wildly different grip ranges depending on length — from a thin 0.5–6.5mm stack up to a thick 11.0–15.5mm stack. Length is what sets the grip.

One thing to keep in mind on thick stacks: the longer the total grip length (the total thickness of sheets being joined), the more difficult it becomes to lock the rivet. And if you’re tired of stocking ten sizes, the wide-range rivets pay off — their extended grip range means fewer different rivet sizes to stock and faster work without constant size changes.

Material: Match It or Watch It Corrode

This is the rule that bites people on Montana exteriors. Fastener material selection affects joint strength, corrosion resistance, and long-term performance. The critical rule: match your rivet material to your base material to prevent galvanic corrosion.

Material	Strength	Corrosion resistance	Best for
Aluminum	Lower	Good	Lightweight assemblies, indoor use
Steel	High	Moderate (can rust)	Strength-critical, painted/indoor
Stainless	High	Excellent	Outdoor, moisture, marine

Mismatched metals fail fast. An aluminum rivet in steel sheet corrodes rapidly in outdoor conditions. A steel rivet in an aluminum sheet causes the aluminum to deteriorate. Aluminum with aluminum, steel with steel, stainless with stainless. No exceptions on anything that sees weather.

Aluminum is the easy-setting choice for light work. Aluminum rivets are softer and easier for cordless tools to set, extending battery runtime. Steel brings strength but rust risk: steel rivets deliver high shear and tensile strength for structural connections, heavy-duty brackets. Use steel rivets with steel materials in painted or indoor environments where rust protection exists.

For gutters, flashing, trailer panels, and anything living through freeze-thaw, stainless is the answer. Stainless steel rivets cost more but provide excellent corrosion resistance for outdoor installations, marine equipment, food processing equipment, and anywhere moisture exposure causes rust concerns. The catch is force — stainless rivets demand maximum pulling force — verify your cordless tool’s capacity handles the rivet size you’re installing.

Choosing the Tool

Tool choice follows volume and rivet size. Manual hand-tools for occasional use, cordless guns for site mobility, or pneumatic tools for high-volume production. The trap is buying a tool that can’t generate enough pull for bigger or stainless rivets.

Pneumatic pop tools get rated by pulling force, and force tracks rivet diameter:

Tool class	Pulling force	Max rivet
Pneumatic (smaller)	11,000 N	5mm
Pneumatic (larger)	18,000 N	6.4mm

On the cordless side, a high-end gun shows what’s possible: 20,000 N of pulling force with a stroke length of 30 mm gives you the power to complete the larger diameters effortlessly, and it can fasten all blind rivets including aluminum, steel, stainless steel and copper from 4.8 mm, 6.0 mm, 6.4 mm and 7.0 mm. Runtime depends on rivet size and material — pulls up to 900 rivets with a rivet size of 4.8 mm in aluminum or 500 rivets with a size of 6.4 mm in aluminum on a fully charged 2.0 Ah battery pack.

Bottom line on capacity: steel rivets require more pulling force, reducing battery runtime compared to aluminum. Stainless and big diameters demand the most. Check the tool’s rated force against the rivet you’re actually setting before you buy.

Installation Basics

The hole prep decides whether the joint holds. Drill precise holes, deburr edges, and ensure the fastener material is compatible with your workpiece to prevent corrosion.

Drill size matches the rivet diameter closely — a 4.8mm rivet runs in a 4.9mm hole, a 4.0mm rivet in a 4.1mm hole. Tight, clean, deburred.

Two things to set expectations on. First, sealing: riveted joints are neither airtight nor watertight unless special seals or coatings are used. If you need a weather seal on a gutter or panel, you’re adding sealant — the rivet alone won’t do it. Second, permanence: since rivets are permanently installed, they have to be removed by drilling them out, a laborious task. Plan the joint right the first time.

Frequently Asked Questions

What’s the difference between a blind rivet and a solid or pin-style fastener? A blind rivet installs entirely from one side, which is why it dominates sheet metal and panel work where you can’t reach the back. Blind (pop) rivets are installed from one side, while solid or pin-style fasteners require access to both sides.

Why does matching rivet material to the base metal matter so much? Mismatched metals set up galvanic corrosion in the presence of moisture, which eats the joint. The critical rule: match your rivet material to your base material to prevent galvanic corrosion. The failure is specific: an aluminum rivet in steel sheet corrodes rapidly in outdoor conditions. A steel rivet in an aluminum sheet causes the aluminum to deteriorate.

Which rivet material holds up best outdoors and around moisture? Stainless. Stainless steel rivets cost more but provide excellent corrosion resistance for outdoor installations, marine equipment, food processing equipment, and anywhere moisture exposure causes rust concerns. Just confirm your tool can generate the force, since stainless rivets demand maximum pulling force.

Should rivets ever be used in thick material or pure pull-out loads? No. Rivets are shear fasteners. Rivets should not be used in thick materials or in tensile applications, as their tensile strengths are quite low relative to their shear strengths.

How do I pick the right size? Match diameter and length to the material stack. Select a rivet diameter and length that matches your material thickness and grip range. If your thicknesses vary across a job, a multigrip or unigrip rivet covers a wider band — one size can replace three standard rivets.

What drill bit goes with which rivet? The hole is sized just over the rivet diameter — for example, a 4.8mm rivet uses a 4.9mm drill, and a 4.0mm rivet uses a 4.1mm bit. Deburr after drilling so the head seats clean.

Are riveted joints watertight? Not on their own. Riveted joints are neither airtight nor watertight unless special seals or coatings are used. Add sealant for any weather-facing joint.

What’s a structural rivet do that a standard one doesn’t? It locks the mandrel in place for more holding power. They are designed to create a mechanical interlock, where the mandrel stays within the rivet post-installation to increase shear strength. For the heaviest connections, monohucks provide lockbolt-style strength in a blind fastener format.