What is a Spud Wrench?

Regardless of whether you are a DIYer or a professional plumber, a wrench is an inseparable part of your arsenal. When it comes to wrenches, there have numerous categories, one of the most common being a spud wrench.

A spud wrench is an adjustable wrench, having a narrow spike as a handle, and can be used for lining up the holes for bolts while doing things like sink fitting, pipe fitting, etc. The bolts can then be set in place and tightened.

The word, ‘spud’ originates from the Irish culture who would call the knife they used to cut potatoes a spud. Due to the similarity between that knife and the handle of the spud wrench, the name caught on over time.

A spud wrench was first introduced as the Maddock Spud by Thomas Maddock in the early 20th century. The design was bought by the Standard toilet company. Over the years, modifications were made to the original design to result in what we now refer to as a spud wrench.

Anyhow, in our guide below, we have detailed everything you need to know about a spud wrench, including the method to use it, where to use and its various subcategories.

So, let’s get started!

How to Use a Spud Wrench?

Using a spud wrench is fairly simple which allows the required job to go on smoothly.

So, firstly, the hole, where a bolt is to be inserted, is aligned using the spike. The process of alignment could include widening the hole or digging into it. A bolt is then, placed in the hole. Finally, the wrench is turned around to secure both the nut on one end and the washer on the other.

What is a Spud Wrench Used for?

A spud wrench is essentially an open-ended wrench that is used for tightening or loosening a variety of fasteners, including nuts and bolts.

It is mainly used for aligning holes in steel construction frames since it is quite a predicament to ensure the alignment of holes during the assembly process. Luckily, a spud wrench turns out to be just the perfect tool for the job.

Apart from that, a spud wrench is often used to loosen spud nuts found in the toilets as well as for the installation of water heaters, radiators, and other large devices.

Types of Spud Wrenches

Spud wrenches come in three different types.

  • Ironworker’s Spud Wrench / Construction Wrench
  • Plumber’s Spud Wrench
  • Radiator Valve Spud Wrench

Ironworker’s Spud Wrench / Construction Wrenches

The ironworker’s spud wrench gets its name from the ironworkers who used this wrench while lining up large beams and girders to construct buildings. The fact that the ironworker’s spud wrench worked with those beams and girders proves its durability and strength.

Ironworker’s Spud Wrench / Construction wrenches can be sub-categorized into Adjustable Spud Wrench and Offset Spud Wrench.

Adjustable Spud Wrench

Also known as a crescent spud wrench, the ability of this wrench’s head to be adjusted to different sizes is what allows it stands out. Its head is also angled in a way as to help it in torque.

It has two jaws; one fixed and one moveable, meaning that only one adjustable spud wrench can be used to tighten or loosen numerous sizes of bolts and nuts.

The only drawback with an adjustable spud wrench is that it doesn’t have a solid grip, unlike a fixed wrench.

Offset Spud Wrench

This type of spud wrench has a curved head that allows for better torque during usage. In tight places, where a standard spud wrench is practically useless, an offset spud wrench comes in pretty handy.

Plumber’s Spud Wrench

Also known as a closet spud wrench, a plumber’s spud wrench was originally crafted to work on pipes containing spuds, meaning that its use was mainly in the toilets with unique designs.

Over the decades, with the introduction of new toilet designs, this tool’s use has dropped significantly. However, when dealing with relatively older plumbing designs, it is often used by plumbers, pipe-fitters, and related professionals. They use it to work the bolts, collar, and other pieces of equipment concerned with the spud.

A plumber’s spud wrench can be sub-categorized into internal spud wrench, external spud wrench, and Adjustable Plumbing spud wrench.

Internal spud wrench

An internal spud wrench is made up of a handle with a tool on either side that spreads outwards. Its unique design allows it to go inside a bolt and move it from within.

Just as a screwdriver, as you turn the tool one way, it causes the bolt to fit while turning it the other way causes the bolt to retract.

External spud wrench

Resembling a standard wrench, an external spud wrench has a handle on one side and an adjustable grip on the other. It is commonly used to clench pipes, large nuts, and whatnot, in order to either hold them in place or turn them such that they can be removed or attached.

The sleek design of this wrench allows you to access bolts and nuts in narrower spaces.

Adjustable Plumbing spud wrench

This is again, a spud wrench that can be adjusted to fit a variety of different sized bolts and nuts. However, it doesn’t have the firm grip of a standard wrench.

Radiator Spud Wrench

This variant of spud wrench is particularly used on radiator valves – to either remove or replace them. It comes in various sizes to match the size of the radiator valve, which usually varies from 1/2’’ to 2’’.

So, basically, a valve is attached to a radiator through a spud. The grooves of a radiator spud wrench get affixed to the nubs located in the interior of the spud. Then, you can use the wrench to either tighten or loosen the spud.

Due to the exclusive nature of spuds found on the radiators, the usage of a radiator spud wrench is very limited. However, it is quite possible to use a few variants of a radiator spud wrench on the spuds that are similar to the ones located on the radiators.

Frequently Asked Questions

What is a Spud Wrench Made Of?

A spud wrench is composed of alloy steel, which explains its durability and toughness.

What is the Difference Between a Spud Wrench and a Pipe Wrench?

A pipe wrench is normally bigger and sturdier than a spud wrench and is required for tightening and loosening pipes and other plumbing connections. On the other hand, a spud wrench works to tighten or remove small nuts and bolts.


All in all, a spud wrench is a fairly simple-to-use tool that comes in pretty handy to tighten or loosen all forms of fasteners, mainly bolts, and nuts. Also, using its pointy handle, you can align the holes, especially in heavier parts, so that a bolt can be secured conveniently.

Liam Weissman

Hello and welcome to PowerToolGenius! My name is Liam and for the last 9 years, I have worked extensively with various power tools and accessories. I have tested hundreds of different brands and models and understand the industry extensively and have been working with tools my entire life!

Recent Posts