A U bolt is a bolt which is shaped like the letter U, with two threaded arms protruding from a curved base. There are a number of uses for U bolts, and a wide variety of sizes are usually available at hardware stores in boxes and as individually sold bulk items. Keeping a few generic U bolts around the house can be useful for people who embark on home improvement projects, as the distinctive design of these bolts can make them very versatile and highly useful in some surprising settings.

A variety of metals can be used to make U bolts, including galvanized and stainless steel. The threaded ends are designed to be used with screws and washers. In some cases, people may also use a crosspiece which spans both threaded arms of the U bolt, to make it more secure in certain settings and uses. Like other bolts, U bolts are designed to be inserted through holes which have already been drilled or punched.

One classic use of the U bolt is in attaching various items to poles and beams. For example, something might be attached to a utility pole with a U bolt, in which case the bolt would straddle the pole, and a crosspiece would be used to keep the bolt snug. U bolts can also be used for things like attaching cables to walls, with the threaded ends of the bolt protruding into a hidden area, while the U faces outwards, allowing users to hold cables, rods, and other materials flat against the wall.

U bolts can also be used as concrete fasteners. In this application, the bolts are pushed into the concrete with the threaded ends facing up while the concrete is still setting, and various objects can be bolted to the concrete with the U bolt. The U shape keeps the bolt in place so that it will not pull out of the concrete, adding security and stability.

It's important to use the right bolt for the job, to reduce expensive repairs and workarounds later. If a U bolt is going to be used in a humid or corrosive environment, it should be made from a metal which resists rust and corrosion. Likewise, it is important to find a bolt which is rated for heavy loads if a bolt will be used to secure extremely heavy objects, and to use a bolt of the proper width when a U bolt will be straddling something as a fastener.