What is a U bolt and how to measure it?- The Ultimate Guide

U bolt is also named U-shaped bolt, U bolt clamp, or U bolt bracelet. Due to the excellent performance and low price, the U bolt is a superb steel fastener throughout the industry.

Various sizes of U bolts are used for different loads and environments, so knowing the exact dimension of the U bolt is the step you should do first when choosing for projects.

stainless steel u boltstainless steel u bolt

What is a U bolt?

U bolt is a curved bolt shaped like a “U”, with both ends threaded to attach nuts and washers. They are manufactured of carbon steel, alloy steel, or stainless steel by cold bending or hot forging process.

How do U bolts work?

U Bolts, nuts and washers are tightened together to provide clamping force and join the two parts together. It can support the hardware through the centre hole and prevent it from moving.

u bolt with a plateu bolt with a plate

What is the application of U bolts?

U bolts are versatile in piping support, and they are also useful in building and construction applications like antenna section secured, wire cable fixation, roofing stability, and automotive components achieved.

u bolt pipe clampu bolt pipe clamp

What are the types of u bolts?

U bolts are commonly classified by bending shape and can be divided into round U bolts, semi-round U bolt, and square U bolt.

types of u boltstypes of u bolts

Each of the three models can be made of corrosion-resistant metals, such as carbon steel, 304 stainless steel, or 316 stainless steel. To further prevent metal corrosion, the zinc coating will be added to the surface of the U bolt by Hot dip galvanising or electric galvanizing.

How to measure a U bolt?

Though there are different types of U bolts, the measurement method is essentially the same.

u bolt dimensionsu bolt dimensions

There are four critical elements in the diagram above:

  • A: Leg length: The length from one thread to the highest point of the U bolt
  • B: Inside width: The Width between two legs
  • C: Rod diameter: The diameter of the rod
  • D: Thread Length: The overall length of one thread

Note: In some countries, the definition of bolt size is not the same as mentioned above, so you need to communicate with the manufacturer before placing an order to avoid unnecessary trouble.

Due to different accuracy, if you measure a U bolt at home, you’d better choose a vernier caliper with the highest efficiency, followed by a bolt template, and then a ruler.

measure bolt diameterHow to measure U bolt diameter

Standard U Bolt Dimensions

Here is a round U bolt size chart for your reference:

Nominal
Size
Leg LengthInside WidthRod DiameterThread Length
(L)(C)(D)(T)
1/2 x 1 1/23″2″1/2″1 1/4″
1/2 x 23 5/8″2 7/16″1/2″1 3/4″
1/2 x 2 1/24 1/8″3″1/2″2″
1/2 x 34 1/2″3 9/16″1/2″2″
1/2 x 3 1/25 1/2″4″1/2″2″
1/2 x 45 3/4″4 9/16″1/2″2″
1/2 x 57″5 9/16″1/2″2″
1/2 x 68″6 5/8″1/2″3″
1/2 x 810 1/4″8 3/4″1/2″3″
1/2 x 1013″10 7/8″1/2″3″
5/8 x 57″5 9/16″5/8″2″
5/8 x 68 3/4″6 3/4″5/8″3″
5/8 x 810 1/4″8 3/4″5/8″3″
5/8 x 1013″10 7/8″5/8″3″
3/4 x 810 1/4″8 3/4″3/4″3″
3/4 x 1013″10 7/8″3/4″3″
3/4 x 1215″12 7/8″3/4″3 3/4″

U bolt size chart

FAQ

What is a U bolt?

U bolt is a curved bolt shaped like a “U”, with both ends threaded to attach nuts and washers. They are made of carbon steel, alloy steel, or stainless steel by cold bending or hot forging process.

What is the application of U bolts?

U bolts are versatile in piping support, and they are also useful in building and construction applications like antenna section secured, wire cable fixation, roofing stability, and automotive components achieved.

What are the types of u bolts?

U bolts are commonly classified by bending shape and can be divided into round U bolts, semi-round U bolt, and square U bolt.

What are the key elements in the diagram of u bolt?

The measurement method is essentially the same for all the types of U bolts
There are four critical elements in the diagram above:

  • A: Leg length: The length from one thread to the highest point of the U bolt
  • B: Inside width: The Width between two legs
  • C: Rod diameter: The diameter of the rod
  • D: Thread Length: The overall length of one thread

What tools I should use when measuring a U bolt?

Due to different accuracy, if you measure a U bolt at home, you’d better choose a vernier caliper with the highest efficiency, followed by a bolt template, and then a ruler.

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