Locked Mandrel Structural Blind Rivet · Steel & A2 Stainless Steel · 3.2 mm to 6.4 mm · Rattle-Free & Vibration Resistant
It is available in steel/steel and A2/A2 stainless steel (body and mandrel in the same material) across four body diameters. The spherical mandrel head design requires a precise hole size — always drill to the exact diameter stated below for the mandrel to lock correctly inside the rivet body.
The U-Bolt blind rivet is a high strength blind rivet engineered for structural and load-bearing applications where a standard open end rivet is not adequate. Its defining feature is the spherical rear mandrel head — when the mandrel is pulled during installation, this sphere forces the blind end of the rivet body to bulge outward into a tight, wide-diameter dome. The mandrel then locks in place inside this dome rather than being ejected, creating a completely rattle-free, sealed joint. The result is significantly higher shear and tensile strength than a standard blind rivet, excellent vibration resistance, and superior hole-filling performance — the rivet fills irregular or slightly oversized holes fully, leaving no play in the joint.
Click each metric to see how the U-Bolt compares to a standard open end rivet.
Body & Mandrel in Steel · Maximum Strength
The highest shear and tensile values available in the U-Bolt range, with both the rivet body and the mandrel in steel. Suited to indoor, sheltered and semi-exposed environments. The standard choice for truck chassis, vehicle bodywork, construction steel framing and any joint where structural load or vibration is a primary concern.
Best for: Truck building · Automotive · Construction · Coach work
Body & Mandrel in A2 · Corrosion Resistant
Full corrosion resistance for outdoor, coastal and high-humidity environments, combined with the U-Bolt's locked mandrel strength advantage; both body and mandrel are A2, so there is no mixed-metal corrosion between them. Slightly lower absolute shear values than steel but far superior long-term joint integrity in wet conditions. Suitable for outdoor structures, marine equipment and food-processing panels where both strength and durability matter.
Best for: Outdoor structures · Marine · Coastal · Food equipment
3.2–6.4
Diameters (mm)
Locked
Mandrel Type
Steel / A2
Materials
19.5 mm
Max Length
A standard blind rivet ejects the mandrel after setting, leaving only the rivet body to carry load. The U-Bolt retains and locks the mandrel inside the rivet body — the spherical mandrel head mechanically interlocks with the bulged blind head. This means both the rivet body and the mandrel core share the load together, resulting in significantly higher shear and tensile values than a standard rivet of the same diameter and material.
This is intentional and is the defining feature of the U-Bolt. The spherical head on the mandrel is larger than the rivet bore — as the mandrel is pulled through, this sphere forces the blind end to bulge around it and lock it in place. The mandrel cannot eject because the sphere is physically trapped inside the set rivet body. This is what delivers the rattle-free, high-strength joint.
Yes — thin sheet metal is one of its primary applications. The spherical mandrel forces the rivet body to fill the hole completely and form a wide, dense blind head even on thin material. This prevents the rivet from pulling through or spinning in the hole, which is a common failure mode of standard rivets in thin gauge steel or aluminium bodywork.
We supply four body diameters: 3.2 mm (lengths 6.5, 9.5 and 11.5 mm), 4 mm (7.5, 10 and 12.5 mm), 4.8 mm (10, 12.5, 14.5 and 16.5 mm) and 6.4 mm (12.5, 14.5, 16.5 and 19.5 mm). Materials are steel/steel and A2/A2 stainless steel, where the body and the mandrel are made from the same material.
Yes. Excel Trading Corporation supplies U-Bolt blind rivets in steel/steel and A2/A2 stainless steel across 3.2, 4, 4.8 and 6.4 mm diameters. We supply to manufacturers, truck builders, automotive fabricators and contractors across India. Call +91 7204435253 or use the Enquire Now button for pricing and bulk availability.
