U-Bolts & J-Bolts: Complete Guide
Pipe Mounting, Concrete Anchoring & Structural Fastening Solutions
U-Bolt Types
Round, square, and specialty U-bolt configurations
J-Bolt Types
Anchor bolts for concrete and foundation work
Size Charts
Complete sizing for pipe diameters and thread sizes
Applications
Plumbing, HVAC, automotive, concrete anchoring
Downloadable Reference Guides
Quick access to all U-bolt and J-bolt specification charts and guides
What Are U-Bolts and J-Bolts?
U-Bolts are bent fasteners shaped like the letter "U" with threads on both ends. They're designed to wrap around pipes, tubes, beams, or other cylindrical objects, clamping them securely to a surface using nuts and often a backing plate. U-bolts are essential for pipe mounting, automotive suspensions, utility installations, and countless structural applications.
J-Bolts are bent fasteners shaped like the letter "J" with threads on the short end. They're primarily used as anchor bolts embedded in concrete or masonry, with the hooked end providing pull-out resistance and the threaded end projecting for attachment of equipment, posts, or structural members.
Key Advantages
U-Bolts: Wrap-around design distributes clamping force evenly, quick installation with no welding or drilling into pipe, adjustable for slight misalignment, easily removable for maintenance.
J-Bolts: Excellent pull-out resistance in concrete, no formwork removal needed, simple installation during concrete pour, cost-effective anchoring solution.
U-Bolt Types and Configurations
Round U-Bolts
Most common type with semicircular bend, designed to wrap around pipes, tubes, and cylindrical objects.
- Semicircular bend shape
- Sized by inside diameter
- Available in pipe and tube sizes
- Steel, stainless, or galvanized
- Standard or heavy-duty options
Square U-Bolts
Square or rectangular bend designed for clamping square tubing, beams, or flat surfaces.
- Square or rectangular shape
- For square tubing or channels
- More surface contact than round
- Prevents rotation of square stock
- Custom sizes available
Semi-Round U-Bolts
Flattened bend design for mounting conduit, cable, or irregularly shaped objects to flat surfaces.
- Wider, shallower bend
- For conduit and cable runs
- Mounts flush to surface
- Electrical and low-profile uses
- Also called strut u-bolts
Heavy-Duty U-Bolts
Thicker material construction for high-load applications like automotive suspensions and industrial mounting.
- Larger rod diameter
- Higher load capacity
- Automotive suspension standard
- Industrial machinery mounting
- Grade 5 or Grade 8 available
Stainless Steel U-Bolts
Corrosion-resistant option for marine, food processing, and outdoor applications.
- 304 or 316 stainless steel
- Excellent corrosion resistance
- Marine and chemical applications
- Food-safe, non-magnetic
- Round or square configurations
Offset U-Bolts
Asymmetric design with one leg longer than the other for mounting near obstructions or uneven surfaces.
- Unequal leg lengths
- For tight clearance situations
- Mounting near walls or obstacles
- Custom configurations available
- Specialty applications
Need Help Selecting U-Bolts?
Our experts can help you determine the right size, material, and configuration for your pipe mounting or clamping application.
Call (866) 573-0445 Browse All U-BoltsJ-Bolt Types and Configurations
Standard J-Bolts
General-purpose concrete anchor bolts with 90-degree bend and threaded end for securing equipment and posts.
- 90-degree hook bend
- Embedded in concrete
- Thread sizes 1/4" to 1" common
- Galvanized or plain finish
- Various hook lengths available
Heavy-Duty J-Bolts
Larger diameter and longer embedment for structural applications and high-load anchoring.
- Larger rod diameters
- Deeper embedment depths
- Structural column anchoring
- Machinery foundations
- High pull-out resistance
Bent Anchor Bolts
L-shaped or custom bent configurations for specific foundation and anchoring requirements.
- Custom bend angles
- L-shaped or multi-bend
- Special embedment needs
- Foundation and structural
- Engineer-specified designs
Hooked Foundation Bolts
Extended hook or plate at embedded end for maximum pull-out resistance in critical applications.
- Extended hook design
- Plate or washer welded on end
- Maximum holding power
- Seismic and wind-load applications
- Building code compliance
Galvanized J-Bolts
Hot-dip galvanized coating provides corrosion protection for outdoor and buried applications.
- Hot-dip galvanized finish
- Outdoor and buried use
- Concrete moisture protection
- Standard and heavy-duty
- Longer service life
Stainless J-Bolts
Maximum corrosion resistance for marine environments, chemical exposure, or food processing facilities.
- 304 or 316 stainless steel
- Marine and chemical resistant
- Food processing applications
- No coating to chip or wear
- Lifetime corrosion protection
Planning Concrete Work with J-Bolts?
Get expert guidance on embedment depth, spacing, and specifications for your foundation or anchoring project.
Call for Technical SupportU-Bolt Sizing and Specifications
U-bolts are sized by three critical dimensions: inside diameter (the size of pipe or object it clamps), inside width (distance between legs), and thread size. Understanding these measurements ensures proper fit and clamping force.
U-Bolt Dimensions Explained
- Inside Diameter (ID): The width across the inside of the bend - should match the outside diameter of the pipe or tube being clamped
- Inside Width: Distance between the two threaded legs - determines clearance for clamping object
- Thread Size: Diameter and pitch of the threaded ends (e.g., 3/8"-16, 1/2"-13)
- Thread Length: Length of threads on each leg, typically 2" to 4" depending on bolt size
- Bend Radius: The radius of the curved portion - affects how tightly it fits around the object
Common U-Bolt Sizes for Pipe
| Pipe Size (Nominal) | Pipe OD | U-Bolt Inside Diameter | Typical Thread Size | Inside Width |
|---|---|---|---|---|
| 1/2" | 0.840" | 7/8" to 1" | 3/8"-16 | 1-1/4" to 2" |
| 3/4" | 1.050" | 1-1/8" to 1-1/4" | 3/8"-16 | 1-1/2" to 2" |
| 1" | 1.315" | 1-3/8" to 1-1/2" | 3/8"-16 | 1-3/4" to 2-1/2" |
| 1-1/4" | 1.660" | 1-3/4" | 3/8"-16 or 1/2"-13 | 2" to 3" |
| 1-1/2" | 1.900" | 2" | 1/2"-13 | 2-1/4" to 3" |
| 2" | 2.375" | 2-1/2" | 1/2"-13 | 2-1/2" to 3-1/2" |
| 2-1/2" | 2.875" | 3" | 5/8"-11 | 3" to 4" |
| 3" | 3.500" | 3-1/2" to 4" | 5/8"-11 | 3-1/2" to 5" |
| 4" | 4.500" | 4-1/2" to 5" | 3/4"-10 | 4" to 6" |
Download U-Bolt Size Chart
Complete sizing for pipe diameters with thread sizes and dimensions.
Download U-Bolt Size Chart (PDF)U-Bolt Selection Tips
Pipe insulation: If pipe is insulated, measure outside diameter WITH insulation and select U-bolt accordingly.
Backing plate: Always use a backing plate or saddle to distribute clamping force and prevent pipe deformation.
Thread engagement: Ensure at least 1.5× bolt diameter of thread engagement in nut for full strength.
Inside width: Must accommodate backing plate thickness plus adequate clearance (typically 1/4" to 1/2").
J-Bolt Sizing and Specifications
| Thread Size | Minimum Embedment | Recommended Embedment | Hook Length | Typical Applications |
|---|---|---|---|---|
| 1/4"-20 | 3" | 4" to 6" | 1-1/2" to 2" | Light equipment, small posts |
| 3/8"-16 | 4" | 6" to 8" | 2" to 3" | Medium equipment, fence posts |
| 1/2"-13 | 6" | 8" to 10" | 3" to 4" | Heavy equipment, structural |
| 5/8"-11 | 8" | 10" to 12" | 4" to 5" | Large machinery, columns |
| 3/4"-10 | 10" | 12" to 15" | 5" to 6" | Heavy structural, seismic |
| 1"-8 | 12" | 15" to 18" | 6" to 8" | Major structural applications |
Download J-Bolt Embedment Guide
Proper embedment depths, spacing, and edge distances for concrete anchoring.
Download Embedment Guide (PDF)⚠️ J-Bolt Installation Critical Factors
Embedment depth: Must meet or exceed minimum specifications for your load. When in doubt, consult a structural engineer.
Concrete strength: J-bolt capacity depends on concrete strength - minimum 3000 PSI for structural applications.
Edge distance: Maintain minimum edge distance (typically 4-6× bolt diameter) to prevent concrete failure.
Spacing: Multiple bolts must be spaced adequately (typically 6-10× bolt diameter) to avoid overlapping stress cones.
Alignment: Use templates or forms to ensure accurate positioning before concrete sets.
Need Engineering Support for Your Project?
We can help with load calculations, embedment specifications, and building code compliance for critical applications.
Call (866) 573-0445Common Applications
U-Bolt Applications
Plumbing & HVAC
Securing water, gas, and HVAC piping to walls, ceilings, and structural members.
- Water supply and drain pipes
- Gas line mounting
- HVAC ductwork supports
- Refrigerant line clamps
- Condenser and compressor mounts
Automotive & Trailers
Essential fasteners for vehicle suspension systems, exhaust mounting, and trailer axle assemblies.
- Leaf spring suspension mounting
- Exhaust pipe hangers
- Trailer axle u-bolts
- Stabilizer bar mounting
- Tow hitch attachments
Electrical & Communications
Mounting conduit, cable trays, and antenna masts for electrical and telecom installations.
- Conduit runs and supports
- Cable tray mounting
- Antenna and tower guying
- Service entrance masts
- Grounding electrode mounting
Marine & Dock
Stainless steel u-bolts for boat rigging, dock construction, and marine infrastructure.
- Boat rigging and mast attachments
- Dock piling mounting
- Anchor rode attachments
- Rail and stanchion mounts
- Marine hardware connections
Industrial Equipment
Mounting machinery, process piping, and equipment in manufacturing and processing facilities.
- Process piping supports
- Machinery attachment points
- Conveyor system mounting
- Hydraulic line clamps
- Compressed air distribution
Agricultural Equipment
Securing equipment, implementing mounting, and trailer assemblies for farm and ranch applications.
- Implement mounting
- Farm trailer axles
- Irrigation system supports
- Livestock equipment
- Grain handling systems
Download U-Bolt Installation Guide
Step-by-step installation with torque specs and best practices.
Download Installation Guide (PDF)J-Bolt Applications
Post and Column Anchoring
Securing wood or steel posts and columns to concrete foundations for buildings and structures.
- Deck and porch posts
- Fence post foundations
- Structural steel columns
- Pergola and gazebo posts
- Sign and light pole bases
Equipment Foundations
Anchoring machinery, HVAC units, and industrial equipment to concrete pads and foundations.
- HVAC equipment pads
- Generator foundations
- Pump and compressor mounting
- Machine tool bases
- Tank and vessel anchoring
Building Foundations
Connecting structural elements to concrete foundations in residential and commercial construction.
- Sill plate anchoring
- Shear wall holdowns
- Beam pockets and ledgers
- Seismic retrofit connections
- Foundation-to-frame ties
Dock and Marine
Anchoring dock hardware, bollards, and marine structures to concrete docks and seawalls.
- Dock cleat mounting
- Bollard anchoring
- Seawall cap connections
- Gangway attachments
- Pile cap hardware
Guardrail & Safety
Mounting guard rails, safety barriers, and protective equipment to concrete surfaces.
- Parking lot guardrails
- Safety rail posts
- Barrier wall connections
- Fall protection anchors
- Loading dock bumpers
Utility & Infrastructure
Anchoring utility poles, communication towers, and infrastructure equipment to concrete bases.
- Utility pole anchors
- Traffic signal foundations
- Street light pole bases
- Communication tower anchors
- Transit infrastructure
Download Anchor Bolt Selection Guide
Material selection, load calculations, and application recommendations.
Download Selection Guide (PDF)Ready to Order U-Bolts or J-Bolts?
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