WHAT IS A U-BOLT AND HOW DO YOU MEASURE THEM?

U-Bolts

U-Bolts are probably the most common type of pipe support. Basically a length of round threaded bar which is bent into a “U” shape with the primary purpose of fastening a pipe or tube to a surface. Though because of the very simple design it can be used for a multitude of other purposes. 

Trying to determine the correct size u-bolt for your application can be a daunting task. Part of this is to do with old pipework engineering speak. U-bolts are traditionally used to clamp pipes into place. Pipes are tubes and engineers who design pipe systems are wholly concentrated on the inside of the tube – because from there they can determine how much fluid or gas can flow through the pipe.

Makes sense – for them. So they will ask for a u-bolt to clamp a “50 nominal bore pipe” which means “Please can I have a U-bolt that will hold a pipe that has an inside diameter of 50 mm” (Not strictly accurate, but close for our purposes). Now, a standard pipe with 50 mm inside diameter will have a 60.3 mm outside diameter.  So “Please can I have a U-bolt that will hold a pipe that has an inside diameter of 50 mm” actually means “Please can I have a U-bolt that will hold a pipe that has an outside diameter of 60.3 mm”

Still with us? So to hold that 50 Nominal bore pipe actually needs a u-bolt that has between 65 and 70 mm depending on how much clamping is to take place. This is why traditionally, u-bolts are labelled the way they are – in Nominal Bore – all very frustrating for non pipe work engineers.

RF U BOLTS

So step forward ours, the new and best way to measure a u-bolt. Using this diagram we can see the key elements:

• Material / finish

• Thread size / bar Diameter

• Thread Length

• Inside Diameter (Distance between the legs)

• Inside height

Those five qualities will uniquely define any u-bolt and RF are now utilising that in our naming conventions

Old Convention: T304 Stainless Steel 50 Nominal Bore gripping u-bolt (Only the dedicated expert will understand that)

New Convention: U-Bolt M10 *35mm Thread, 65mm Inside Diameter, 96mm Inside Height T304 Stainless Steel

Anyone should be able to read that and know if it will suit their needs

So for example:

Thread Size=M

Inside Diameter=D

Inside Height=H

Thread Length=T

RF U BOLT= UBOLT/MATERIAL/M*D*H*T

Example: UBOLT/GALV/M6*34*75*20