Spud Wrenches: The Ironworker's Most Important Tool
Ask an ironworker which tool they would grab if they could only keep one, and most will reach for the spud wrench. It tightens structural bolts on one end and aligns bolt holes with a long tapered handle on the other, which is exactly why it lives on the hip of nearly every steel erector in the field. This guide explains what a spud wrench is, what it is used for, how to use one correctly during steel erection, and how it differs from a standard combination wrench.
What Is a Spud Wrench?
A spud wrench, also called an erection wrench, is a structural-steel hand tool with a single open-end or box wrench head at one end and a long, gently tapered handle at the other. The wrench end turns the heavy hex nuts used in structural connections, while the tapered handle, the "spud," slides into a bolt hole to lever two pieces of steel into alignment. That dual purpose is what sets it apart from an ordinary wrench and why it is the signature tool of the ironworking trade.
The heads are sized for the heavy hex nuts and bolts common in structural work, with nominal openings typically ranging from about 3/4 inch up to 1-1/4 inch and beyond. Wrenches are matched to either U.S. heavy nuts or U.S. regular nuts, so the opening has to fit the connection hardware on the job. Quality erection wrenches are drop-forged from alloy steel to survive the leverage and impact of field work, and many include a tether hole so the tool can be tied off when working at height. You can see the range in our construction and structural wrenches category.
Variants include offset and straight patterns, double-head spud wrenches with two sizes, and ratcheting models that speed up run-down. For broader selection across styles, browse all wrenches at Midland Tool.
What Is a Spud Wrench Used For?
The spud wrench is built for steel erection and heavy structural assembly, where holes never quite line up on the first try and bolts have to be drawn up tight. Common uses include:
- Aligning bolt holes in beams, columns, and plate by driving the tapered handle through the connection to pull the steel into register.
- Snug-tightening structural bolts and running down heavy hex nuts before final tensioning.
- Bridge, tower, and high-rise erection where ironworkers connect members hundreds of feet up.
- Mechanical and millwright work, setting flanges, base plates, and large equipment that uses heavy bolting.
- Prying and leverage tasks, using the handle to coax members into position.
Per AWS and AISC field practice, the snug-tight condition is reached after a few impacts of an impact wrench or the full effort of an ironworker on a spud wrench, which is why the tool is sized for serious leverage. For the powered side of the same job, see our sockets, ratchets, and impact attachments.
How to Use a Spud Wrench
Using a spud wrench well is about sequence and control. Here is the basic field process for making a bolted connection:
1. Land and hold the member
With the beam or column set, do not release the load from the hoist line until the connection is secured with at least two bolts drawn up wrench-tight, as required by OSHA steel erection rules.
2. Spud the first hole
Drive the tapered handle into an open hole to lever the mating piece into alignment. The taper does the work, pulling the plies together so the holes register.
3. Set and start your bolts
With a hole aligned, drop in a bolt and start the heavy hex nut by hand, then run it down with the wrench end. Move to the next hole, re-spud if needed, and repeat.
4. Snug-tighten the connection
Bring all plies into firm contact by snug-tightening with the wrench end or a few impacts from a powered wrench. Snug tight is the starting point for any final pretensioning method.
5. Tie off the tool at height
When working elevated, run a lanyard through the tether hole so a dropped wrench never becomes a hazard below. Choose the correct opening for your hardware from our wrenches and adjustable wrenches, and confirm bolt grade and torque against the engineer's specs.
Spud Wrench vs Combination Wrench
A spud wrench and a combination wrench can both turn a nut, but they are built for different worlds. The spud is a structural and alignment tool; the combination wrench is a general-purpose mechanic's tool. Here is the comparison:
| Spud Wrench | Combination Wrench | |
|---|---|---|
| Primary job | Aligning holes and bolting structural steel | General fastening and mechanical work |
| Handle | Long tapered "spud" for alignment and leverage | Straight handle, no alignment function |
| Heads | Single head sized for heavy hex nuts | Open end and box end, same size |
| Typical user | Ironworkers and steel erectors | Mechanics, maintenance, and assembly techs |
| Tether hole | Common, for work at height | Rare |
If your work is general fastening rather than steel erection, a combination set is the better starting point, see our guide to the adjustable wrench for another versatile option. For structural connections, the spud wins every time.
Spud Wrench FAQs
The name comes from the long, tapered handle, the "spud," which resembles an old spud or spike used for digging and prying. Ironworkers drive that taper into bolt holes to align steel, so the tool took the name of its most distinctive feature. It is also widely called an erection wrench.
It does two jobs: the tapered handle aligns bolt holes in structural steel, and the wrench head tightens the heavy hex nuts used in those connections. Ironworkers use it to land members, draw plies together, start bolts, and snug-tighten connections during steel erection.
Match the wrench opening to the heavy hex nut on your connection and confirm whether the job uses U.S. heavy nuts or U.S. regular nuts. Common nominal openings run from about 3/4 inch to 1-1/4 inch. When in doubt, carry the sizes that match the bolt diameters called out on your erection drawings.
A spud wrench is used to snug-tighten connections and bring plies into firm contact. Final pretensioning of high-strength bolts is then completed by an approved method such as turn-of-nut, calibrated wrench, or tension-control bolts, often using a powered impact or shear wrench. The spud sets the stage; the final tension follows the engineer's specified method.
They are closely related. "Podger" is the term used in the UK and parts of Europe for a spanner with a tapered alignment spike, the same concept as the North American spud wrench. A podger may pair the spike with a ratchet or scaffold-size opening, but both tools align holes and turn nuts.
Midland Tool stocks construction and structural wrenches, including spud and erection wrenches, alongside the sockets, impacts, and bolting accessories that go with them. Reach out to our team for sizing help, or ask about our StockUp program and bolting services to keep the right hardware on hand for every job.
Ready to Get Started with Spud Wrenches?
From steel erection to heavy mechanical bolting, the right spud wrench keeps your crew moving and your connections square. Shop Midland Tool's construction and structural wrenches, then round out the kit with sockets, ratchets, and impact attachments. A Michigan-based industrial supplier since 1962, Midland also offers a StockUp program and bolting services to keep your jobsite stocked. For installation standards, see AISC's bolt installation guidance, OSHA's steel erection rule for beams and columns (1926.756), and the Klein Tools spud wrench lineup.
