Square U-Bolts
Stainless Steel Square U-Bolts
Dale Fastener Supply is a trusted manufacturer and distributor of 304 stainless steel square U-bolts. As a dedicated square U-bolt supplier, we can accommodate both custom and standard size requirements. Our 304 SS square U-bolts are particularly popular for their excellent corrosion resistance, making them ideal for saltwater environments such as boat trailers, lifts, docks, boathouses, and bulkheads. Beyond marine applications, our square U-bolts are also widely used in heavy equipment projects. We offer same-day shipping for stock U-bolts and provide quick turnaround times for custom orders.
Custom Square U-Bolts
In addition to our standard 304 SS square U-bolts, we also manufacture custom square U-bolts in materials such as carbon steel, A193 B7 4140, and 316 stainless steel, with a range of finishes including Hot Dip Galvanized, Zinc Plated, and Pro-Coat. All U-bolts are produced at our Houston, Texas facility, allowing us to offer quick lead times and competitive pricing. For custom orders, please request a quote today.
Stock bolts have a minimum purchase of $25.
Order Stock 304 SS Square U-Bolts
Our Products
| Name | Long Description | Material | Finish | SKU | |
|---|---|---|---|---|---|
| 1/2 x 4 1/2 Square U-Bolt (U-SQR), 304 Stainless Steel (SS) | 1/2″-13 x 2 1/8″ x 4 1/2″ x 2″ | 304 Stainless Steel (SS) | 304 Stainless Steel (SS) | SSTSQ122412 | |
| 1/2 x 4 1/2 Square U-Bolt (U-SQR), 304 Stainless Steel (SS) | 1/2″-13 x 3 1/8″ x 4 1/2″ x 2″ | 304 Stainless Steel (SS) | 304 Stainless Steel (SS) | SSTSQ123412 | |
| 1/2 x 5 1/2 Square U-Bolt (U-SQR), 304 Stainless Steel (SS) | 1/2″-13 x 2 1/8″ x 5 1/2″ x 2 1/2″ | 304 Stainless Steel (SS) | 304 Stainless Steel (SS) | SSTSQ122512 | |
| 1/2 x 5 1/2 Square U-Bolt (U-SQR), 304 Stainless Steel (SS) | 1/2″-13 x 3 1/8″ x 5 1/2″ x 2 1/2″ | 304 Stainless Steel (SS) | 304 Stainless Steel (SS) | SSTSQ123512 | |
| 1/2 x 5 1/2 Square U-Bolt (U-SQR), Zinc Plated | 1/2″-13 x 2 1/8″ x 5 1/2″ x 2″ | Carbon Steel (CS) | Zinc Plated | ZPSQ122512 | |
| 1/2 x 5 1/2 Square U-Bolt (U-SQR), Zinc Plated | 1/2″-13 x 3 1/8″ x 5 1/2″ x 2″ | Carbon Steel (CS) | Zinc Plated | ZPSQ123512 | |
| 1/2 x 6 1/2 Square U-Bolt (U-SQR), 304 Stainless Steel (SS) | 1/2″-13 x 2 1/8″ x 6 1/2″ x 2 1/2″ | 304 Stainless Steel (SS) | 304 Stainless Steel (SS) | SSTSQ122612 | |
| 1/2 x 6 1/2 Square U-Bolt (U-SQR), 304 Stainless Steel (SS) | 1/2″-13 x 3 1/8″ x 6 1/2″ x 2 1/2″ | 304 Stainless Steel (SS) | 304 Stainless Steel (SS) | SSTSQ123612 | |
| 1/2 x 7 1/2 Square U-Bolt (U-SQR), 304 Stainless Steel (SS) | 1/2″-13 x 2 1/8″ x 7 1/2″ x 2 1/2″ | 304 Stainless Steel (SS) | 304 Stainless Steel (SS) | SSTSQ122712 | |
| 1/2 x 7 1/2 Square U-Bolt (U-SQR), Zinc Plated | 1/2″-13 x 2 1/8″ x 7 1/2″ x 2″ | Carbon Steel (CS) | Zinc Plated | ZPSQ122712 | |
| 3/8 x 3 Square U-Bolt (U-SQR), 304 Stainless Steel (SS) | 3/8″-16 x 2 1/8″ x 3″ x 1″ | 304 Stainless Steel (SS) | 304 Stainless Steel (SS) | SSTSQ3823 | |
| 3/8 x 3 Square U-Bolt (U-SQR), Zinc Plated | 3/8″-16 x 2 1/8″ x 3″ x 1″ | Carbon Steel (CS) | Zinc Plated | ZPSQ3823 | |
| 3/8 x 4 Square U-Bolt (U-SQR), 304 Stainless Steel (SS) | 3/8″-16 x 3 1/8″ x 4″ x 1 1/2″ | 304 Stainless Steel (SS) | 304 Stainless Steel (SS) | SSTSQ3834 | |
| 3/8 x 4 Square U-Bolt (U-SQR), Zinc Plated | 3/8″-16 x 3 1/8″ x 4″ x 1 1/2″ | Carbon Steel (CS) | Zinc Plated | ZPSQ3834 |
Materials and Finishes for Square U-Bolts
We stock square U-bolts in materials and finishes to match the environment they will be installed in, and we manufacture others to order:
- 304 stainless steel: In stock, resists rust in wet and salt water environments.
- Zinc plated carbon steel: In stock, economical protection for lighter exposure.
- 316 stainless steel: Made to order, with better resistance to chlorides and harsh chemicals.
- Hot-dip galvanized: Made to order, a thick zinc coating for outdoor and damp locations.
- Pro-Coat: Made to order, our highest level of protection for carbon steel.
- A193 B7 4140: Made to order for higher-strength applications.
For projects that need a specific base material, send us your specification and we will confirm what we can stock or source.
Common Uses for Square U-Bolts
Square U-bolts fit flat-sided stock that a round U-bolt cannot seat against evenly, such as square tubing, posts, and flat plates. Our stock sizes serve marine and heavy equipment work, and the right bolt depends on the width of the material, the load, and the environment the installation will face.
Marine and Waterfront Applications
Salt water, spray, and constant moisture wear down plated steel quickly on docks, boat lifts, boathouses, and bulkheads. Our stock 304 stainless steel square U-bolts resist rust at the source where carbon steel would corrode. Choosing stainless up front helps avoid early replacement and repeat maintenance on marine and waterfront hardware.
Trailers and Heavy Equipment Mounting
Boat trailers and heavy equipment run heavy loads and constant movement through every fastener in the assembly. Our U-bolt plates pair with square U-bolts to spread the load across the connection point. The right inside width and thread length depend on the frame member being clamped and the thickness of what is being secured.
Square Tubing and Post Mounting
Equipment, signs, and brackets that mount to square tubing or square posts need a fastener with flat sides to match. A square U-bolt wraps the post and clamps the item against it, so the fit stays snug and the load stays where it belongs. When the post or tube is a size we do not stock, we can make the U-bolt to match.
Request a Quote for Square U-Bolts
Need a size outside our stock range? Send us your dimensions, material, and finish, and our team will quote stock sizes or custom U-bolts made to your print at our Houston facility.
FAQs
What square U-bolt sizes do you stock?
Our stock square U-bolts come in 3/8″ and 1/2″ diameters with 2 1/8″ and 3 1/8″ inside widths, in 304 stainless steel and zinc plated carbon steel. Use the filters in the product table to narrow by size, material, and finish. Anything outside these sizes can be made to order.
How do I measure for a square U-bolt?
Measure the width of the material you are clamping and match it to the inside width of the U-bolt, so the fit stays snug and the clamping force holds. Then choose a thread length that clears the thickness of what you are securing plus the nuts and washers. If your measurements fall between our stock sizes, send us the dimensions and we will quote a custom size.
What is the difference between a square U-bolt and a standard U-bolt?
A standard U-bolt has a rounded bend that wraps around pipe and other round stock. A square U-bolt has a squared bend with parallel legs, so it seats against square tubing, posts, and flat-sided members. The shape of what you are securing decides which one fits.
What is the difference between 304 and 316 stainless steel square U-bolts?
Both resist rust, but 316 contains molybdenum, which gives it better resistance to chlorides and harsh chemicals. Our stock square U-bolts include 304 stainless steel. We manufacture 316 stainless steel square U-bolts to order for more demanding environments.
Our team is ready to provide a personalized quote for your project needs. Whether you need standard or custom fasteners, we have the expertise and quality products to meet your requirements. Contact us now to get started.
Specials are made to order with short lead times.
The Dale Company can ship special orders the same day, including a ’24 hour service’.
Let us know about your project and a Dale Company representative will contact you.
Have Questions? Give us a Call!
(713) 928 3437If you have any questions about the products, quotes, or desire any additional information please get in touch. One of our Dale representatives will reach out to you shortly to address any of your concerns or inquiries.
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