A common wrench is perfect for loosening nuts and bolts. But if you need to adjust round, smooth or irregular-shaped objects, a traditional wrench simply won’t work.

A strap wrench has long been the secret weapon of mechanics and plumbers while staying largely unknown to most DIYers. We’ll take a look at what makes a strap wrench valuable, how to use one and how to select the right style for your project.

What Is a Strap Wrench?

A strap wrench grips an object with a strap or chain and holds it firm so you can tighten or open it. They come in various sizes, materials and styles to tackle a range of jobs.

Strap wrenches are commonly used for household tasks like opening jars, loosening or tightening plumbing fixtures, and automotive work such as changing oil filters. But they can also be used for things like wrapping a strap around a bundle of pipe or lumber, or to carry things.

Types of Strap Wrenches

Oddly, there’s no industry standard for describing strap wrenches. Think about which strap wrench style and materials can best help you achieve your goal.

Most manufacturers describe a given wrench by the length of its strap and strap material. However, some manufacturers list the overall length of the strap, while others list the maximum diameter it can circle. You might see identical wrenches listed as an “8-in. nylon strap wrench” or “24-in. nylon strap wrench.” You’ll have to look closer to realize one describes the overall length, and the other the usage.

In general, most strap wrenches can be categorized by strap material, handle vs. compact, and oil filter vs. general use.

Materials: Nylon, rubber and metal chain are the most common. Soft materials are perfect for loosening or tightening items you don’t want to mar, like plumbing fixtures or stuck jar lids.

Metal strap wrenches, however, provide a more aggressive “bite” into the surface of the material. These almost always leave a mark, but they also almost always accomplish the task.

Note: Don’t confuse a metal chain strap wrench with a soil stack cutter! Although they look similar, a soil stack cutter (sometimes called a pipe cracker) breaks cast iron or ceramic soil stack pipes into short lengths for easy removal.

Integrated handle or compact. Some strap wrenches come with an integrated handle that allows you to tighten the strap loop and get cranking. Others require a socket tool like a driver or ratchet to tighten and crank. These compact strap wrenches trade convenience for size. They fit in smaller spaces where a handle would make cranking difficult or impossible.

Oil filter or general use. Oil filter strap wrenches are sometimes more limited by loop size, but this isn’t always the case. Solid metal band straps are frequently more limited in size, while nylon straps have more range. Always check the size of the strap before making your purchase.

How To Use a Strap Wrench

No matter the type of strap wrench you choose, the basic steps remain the same.

Select the proper size and material. As mentioned, the size and material of the strap wrench will impact how it interacts with the workpiece. Use a wrench with a softer strap material to prevent scuff marks on the workpiece.

Place the strap around the workpiece. It’s usually easiest to feed the end of the strap through the wrench, then slip the whole loop over the workpiece. One exception: When you can’t access to the end of the workpiece, such as loosening a drain line. In that case, reach the strap around the workpiece and back to the wrench.

If using a handle strap wrench, orient the tool so the teeth pull back on the strap in the direction you’re turning.

Hand-tighten the strap. Usually this means pulling the loose end of the strap through the wrench to create a snug fit.

Crank with the handle or socket tool. Using the handle or socket tool, crank the wrench in the proper direction to tighten or loosen it. The strap will apply near uniform pressure around the workpiece, moving it in the desired direction.