Pipe Wrench

What is a pipe wrench?

A pipe wrench is a large adjustable wrench with hardened, serrated jaws that bite into round pipe. The upper jaw pivots to increase grip as you pull, allowing you to turn threaded pipes and fittings without slipping. It is a go-to tool for working on steel, iron, and some softer metal pipes used in plumbing and heating systems.

How it works

A pipe wrench uses a self-tightening action. The hook jaw (upper, movable jaw) pivots slightly and has teeth angled toward the handle. As you pull the handle in the correct direction, the jaw digs in, increasing grip. The knurled adjustment nut changes the jaw opening to match pipe diameter. The opposing fixed jaw (heel jaw) provides the second contact point. Together they create a secure hold on round surfaces that smooth-jawed wrenches struggle with.

Key parts:
- Hook jaw and heel jaw with serrated teeth
- Adjustment nut (knurl) to set jaw opening
- Frame and handle (cast iron or aluminum)

Common DIY uses

• Breaking loose rusted or painted threaded joints on galvanized or black iron pipe
• Tightening or removing nipples and couplings on water heaters and boilers
• Adjusting threaded black iron gas pipe runs and unions (check local code and consider hiring a licensed pro for gas work)
• Holding one fitting while turning another, such as on radiator valves or well pump piping
• Removing seized steel cleanout plugs or stuck lawn irrigation risers

Types of pipe wrenches

• Straight pipe wrench: The classic Stillson pattern used for general work. Available in many sizes.
• Offset pipe wrench: Jaw is angled to reach around obstructions and close to walls.
• End pipe wrench: Short jaw and narrow head for work in tight spaces, especially near floor or wall.
• Chain wrench: Uses a chain instead of jaws to wrap large or irregular shapes; useful on large diameter pipe.
• Strap wrench: Uses a non-marring strap on polished surfaces like chrome or plastic where teeth would damage the finish.
• Aluminum-handled models: Same function as cast iron but lighter, reducing fatigue for overhead work.

Choosing the right pipe wrench

• Size: Wrenches are sized by overall length. As a rough guide, a 14 in wrench works well for 1/2 to 1 in pipe, an 18 in for 1 to 2 in, and a 24 in for larger. Bigger handles increase leverage and grip.
• Jaw capacity: Check the maximum pipe diameter the wrench can open to; make sure it covers your fittings.
• Weight: Aluminum is lighter and easier to handle overhead; cast iron is tough and often costs less.
• Head style: Straight for general use, offset or end for tight or awkward spots.
• Condition: Sharp, clean teeth and a smooth-turning adjustment nut are musts. Avoid worn, rounded teeth.

How to use a pipe wrench effectively

1. Fit the jaws to the pipe: Open the jaws and place them so the teeth contact firmly, with the hook jaw on the side you will pull toward. Close the jaws until they seat with slight clearance; do not over-open.
2. Orient for the pull: Always pull so the hook jaw tightens onto the pipe. If the wrench slips, flip it over.
3. Use two wrenches when needed: On threaded joints, place one wrench to hold the stationary side and a second to turn the other, applying opposing torque. This reduces stress on pipes and nearby joints.
4. Position near the joint: The closer the wrench is to the threaded joint, the less chance of bending or twisting the pipe.
5. Apply steady pressure: Pull smoothly, keeping your other hand clear of pinch points. If extra leverage is needed, step up to a longer wrench rather than using a cheater bar.
6. Protect finishes: On chrome or finished surfaces, use a strap wrench or wrap the fitting with a protective sleeve if you must grab it with teeth. For sacrificial parts being discarded, use the pipe wrench directly.

Safety tips:
- Wear gloves and eye protection; chipping rust and sudden slips can injure hands and eyes.
- Stand balanced and pull the handle toward you; do not push down with your palm near the teeth.
- Check for gas lines or sensitive components nearby before applying heavy force.

Care and maintenance

• Clean the teeth after use with a wire brush to remove debris and rust.
• Lightly oil the adjustment nut and pivot to keep movement smooth.
• Inspect for chipped or rounded teeth; replace the hook and heel jaw kits if worn.
• Store with the jaws closed lightly to protect teeth and prevent bending.
• Keep the wrench dry to reduce corrosion; wipe down after damp jobs.

Common mistakes to avoid

• Using on chrome-plated or soft plastic fittings; the teeth will gouge. Switch to a strap wrench for finished surfaces and use pliers or specialty tools for PVC.
• Grabbing hex nuts or valves designed for flat wrenches; you can deform them. Use an adjustable wrench or box wrench instead.
• Pulling in the wrong direction so the jaw opens and slips; always orient the hook jaw to bite as you pull.
• Using too small a wrench; small handles invite cheater bars and slippage. Choose a longer wrench for more torque.
• Over-tightening threaded joints; this can crack fittings or distort threads. Tighten to snug plus an additional quarter turn as needed, following manufacturer guidance.
• Clamping on thin-wall tubing; the teeth can crush it. Use proper tubing tools.

Related tools and terms

• Adjustable wrench: Smooth jaws for hex nuts; not for gripping round pipe.
• Tongue-and-groove pliers: Good for lighter plumbing work and compression nuts.
• Basin wrench: Reaches faucet nuts behind sinks.
• Strap wrench and chain wrench: Alternatives for delicate or very large objects.
• PTFE thread seal tape and pipe thread sealant: Used on tapered pipe threads to seal joints.
• Nipple extractor: Removes broken or flush nipples when a wrench cannot bite.

Practical examples

• Replacing a rusted water heater nipple: Use one pipe wrench to hold the tank side fitting steady and a second to turn the nipple counterclockwise. Apply steady force; if stuck, add penetrating oil and try again after a short wait.
• Adjusting black iron gas pipe during a remodel: With permits and safety checks, use two wrenches in opposition on unions and couplings to avoid stressing other joints. Verify alignment before final tightening and leak test with approved methods.
• Removing an old galvanized riser in a basement: Place the wrench close to the coupling, orient for the pull, and use an 18 or 24 in wrench for leverage. If the pipe begins to crush, stop and cut the pipe instead, then remove the remaining stub with a smaller wrench or nipple extractor.
• Protecting chrome shower arms: Use a strap wrench to remove or install the finished arm. If the old arm will be discarded, a pipe wrench can help break it loose, but expect tooth marks.

With the right size and technique, a pipe wrench gives you the controlled bite needed to break stubborn threaded joints and assemble secure connections on metal pipe without rounding or slipping.