Product Tutorials: Breakstem Rivets
What They Are
Blind fastening allows joining two or more materials together from one
side of the application.
Breakstem fasteners and installation tools are a high performance blind fastening
system. They consist of a mandrel and body which are combined into a single
assembly. The term "Breakstem" refers to the end result of the placing process,
when the fastener mandrel is gripped by the jaws in the tool nose piece and
snaps off at a pre-determined load, sometimes flush with the fastener head.
Used in all manufacturing industries throughout the world, there is a breakstem
fastener and installation tool to suit virtually every assembly requirement.
 Other
names for rivet features:
• Mandrel (a.k.a. Stem, Nail, Pin)
• Body (a.k.a. Rivet, Shank)
• Head (a.k.a. Flange)
How They Work
 View an interactive demo
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The rivet is placed in position and the installation tool pulls the mandrel.
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This action causes rivet deformation in two ways. Firstly, a bulbed tail
is formed at the back of the rear sheet or the mandrel head pulls into the
rivet body, which pulls the application together (clamp). Secondly, the rivet
expands radially giving hole fill; this action compensates for any hole
irregularity.
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At a pre-determined load the mandrel breaks leaving its tail (mandrel) locked
into the body.
Head Styles
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Dome Head
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The most common and verstile head style
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Twice the diameter of the rivet body
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Sufficient bearing surface for all except extremely soft or brittle materials
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Other names: Protruding, Button, Standard
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Large Flange Head
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Greater under head bearing surface
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Designed fgor extremely soft or brittle materials
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Other names: Mushroom, Brazier
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Countersunk Head
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Specified when a flush surface is required
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Other names: Flat head
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Rivet Styles
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Non-Structural
The mandrel breaks within the rivet body, but is not designed to
break flush with the rivet head. A short length of the mandrel is retained
within the rivet body, but since the mandrel may not break within the shear
plane, it is refered to as non-structural.
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Non-critical applications
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Low strength materials
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Cost effectiveness
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Structural
The mandrel breaks within the shear plane and for several products it is
designed to break near flush with the rivet head.
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Strength critical applications
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Weather resistance
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Sheet separation
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Visual check for rivet placement
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Body Types
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Open End
The end of the rivet is open. The rivet body is hollow through its full length. |
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Closed End
The end of the rivet is solid and remains closed on the blind side after
setting. |
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Large Blind Side Footprint
The shank of the rivet has one or more axial slots which extend from the
underside of the head and terminate short of the open end. The remaining
portion of the shank is a hollow cylinder similar to an open end type. |
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Peel Rivets
A portion of the rivet body is split axially into 2 or more segments. |
Fasteners
| Brand |
Material
(Rivet/Stem) |
Key Features |
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Aluminium/Aluminum
Aluminium/Steel
Steel/Steel
*Tubular component matches rivet |
Avdelmate®
(Non-Structural)
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Two piece fastener
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Extra wide grip range
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Large bearing area against both sides of the application
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Excellent hole fill
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Aluminium/Steel
Aluminium/Stainless
Steel/Steel |
Avex®
(Non-Structural)
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Multi-grip capability
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Good hole fill
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Retained stem
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Large blind side bearing area
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Steel/Steel |
Avibulb®
(Non-Structural)
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High shear and tensile strength
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Good hole fill
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Retained stem
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Large blind side bearing area
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Steel/Steel |
Avibulb® XT
(Structural)
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High shear and tensile strength
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Multi-grip capability
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High residual clamp load
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Stainless/Stainless |
Avinox® XT
(Structural)
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High shear and tensile strength
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High corrosion resistance
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Ideal for applications requiring elevated temperatures
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Multi-grip capability
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Stainless/Stainless |
Avinox®
(Non-Structural)
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High shear and tensile strength
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High corrosion resistance
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Good hole fill
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Retained stem
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Large blind side bearing area
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Aluminum/Steel |
Avseal®
II (Structural)
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Fully annealed sleeve
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Excellent hole fill
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Large hole tolerance
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Internal lock
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Aluminium/Aluminium |
Bulbex®
(Non-Structural)
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Split tail formation for thin sheet and low strength materials
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Multi-grip capability
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Retained stem
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Aluminium/Aluminum
Steel/Steel |
Hemlok®
(Structural)
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Very high shear and tensile strength
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Large blind side bearing area
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Interference lock via splined stem
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Aluminium/Aluminum
Steel/Steel |
Interlock®
(Structural)
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Multi-grip capability
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Fully sealed fastener
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Excellent hole fill
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Mechanically locked stem
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Good sheet take-up performance
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Aluminium/Aluminium |
Klamp-Tite®
(Non-Structural)
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Split tail formation for soft and low strength materials
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Multi-grip capability
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Retained stem
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Aluminium/Aluminium |
Klamp-Tite®
(Structural)
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Split tail formation
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Multi-grip capability
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Optional underhead washer provides weather-proof seal
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Mechanically locked stem for strong, vibration resistant joints
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Aluminium/Aluminum
Steel/Steel
Stainless/Stainless |
Monobolt®
(Structural)
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Multi-grip capability
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Fully sealed fastener
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Visible lock
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Excellent hole fill
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Mechanically locked stem
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Good sheet take-up performance
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Aluminium/Aluminum
Aluminum/Steel
Monel/Steel
Stainless/Stainless
Steel/Steel |
N Rivet
(Non-Structural)
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Low cost
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Quick installation
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Unique mandrel head design for positive retention
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Aluminium/Steel
Monel/Steel
Stainless/Stainless
Steel/Steel |
Q Rivet
(Structural)
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Interference lock via a splined stem
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Stem plugs entire shell length
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Weatherproof
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Steel/Steel
Stainless/Stainless |
Stavex®
(Non-Structural)
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Multi-grip capability
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Good hole fill
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Retained stem
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Large blind side bearing area
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Aluminium/Aluminum
Aluminum/Steel |
T Rivet
(Structural)
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Superior clamp for sheet separation
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Strong, vibration resistant joint
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Mechanically locked stem for vibration resistant joints
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Steel/Steel |
T-Lok®
(Non-Structural)
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‘Peel-type’ tail formation for joining wood to metal
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Wide grip range
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Retained stem
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Rivet Selection
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Grip Range
The thickness of the parent material(s) must fall within the grip range of
the fastener.
Hole Size
It is important to control the hole size accurately in order to ensure optimum
fastener performance.
Corrosion Resistance
Corrosion is best reduced by selecting a fastener material which is the same
as the parent material(s). Stainless steel fasteners offer the best corrosion
resistance.
Special Surface Coatings
For improved corrosion resistance or aesthetics, we can apply various finishes.
Strength Characteristics
Shear and tensile values for the selected fastener must fall within the
application requirements.
Load Spreading
Select a fastener with a large blind side bearing area and/or large flange
head for use in thin or low strength materials. |
Application
Outlined below are some of the most popular fastening scenarios and the
recommended fastening solution for these situations.
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Soft Material to Hard
Soft-to-hard is sometimes assembled by using a backup washer. Preferred practice
is to use a large-flange rivet and set the blind side footprint against the
hard material. |
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Thick and Thin Sheets
Whenever possible, set the blind side footprint against the thicker, stronger
material./ Where the head mist be set against thinner material, use of a
backup washer is desirable. |
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Tubing
Setting the rivet against a flattened section © produces maximum rigidity.
The joint shown in B is slightly less rigid, but entirely satisfactory. The
rivet should not extend through both tube walls as shown in A.
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Plastic and Brittle Materials
When the more fragile plastics are involved, large blind side footprint rivets
should be specified. When the plastic is rigid enough to afford satisfactory
clinching action, standard blind rivets can be set directly against plastics. |
Installation Tools
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30% glass filled nylon
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Durable and robust construction for a long working life
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Comfortable to handle
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Reduced operator fatigue and improved productivity
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Reduced risk of RSI
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High speed assembly
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Ideal for high volume production
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Quick and simple to operate
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Integral stem collectors
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Tamper-proof casings
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Overheat protection
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Portable and easy to handle
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| Tool |
Description |
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nG1 (Hydro-Pneumatic)
Places up to 4.8 mm (3/16") aluminium breakstem rivets and up to 4.0 mm (5/32")
steel breakstem rivets produced by Avdel®. Can also place Avseal®
II 4 and 5 mm sealing plugs. |
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nG2 (Hydro-Pneumatic)
Places up to 4.8mm (3/16") breakstem rivets produced by Avdel®. Can also
place Avseal® II sealing plug up to 7 mm. |
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nG2S
(Hydro-Pneumatic)
Places up to 4.8mm (3/16") breakstem rivets. Can also place Avseal® II
sealing plugs up to 7 mm. |
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nG3 (Hydro-Pneumatic)
Places up to 6.4mm (1/4") breakstem rivets produced by Avdel®, except
Hemlok® structural fasteners. Can also place Avseal® II sealing plugs
up to 9 mm and Avtainer® lockbolts 9.5mm (3/8"). |
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nG4 (Hydro-Pneumatic)
Places Up to 6.4mm (1/4") breakstem rivets produced by Avdel® except
Monobolt® structural rivets. Can also place: Avseal® II sealing plugs,
up to 12 mm Avtainer® lockbolts, 9.5mm (3/8") Avdelok® and Maxlok®
lockbolts 4.8mm (3/16") and 6.4mm (1/4") Hemlok® structural rivets 6.4mm
(1/4"). |
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TX2000®
(Battery)
Places aluminum, stainless, steel to 6.4mm (1/4) and steel 4.8mm (3/16) |
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