What Are Locking Pliers Used For? Common Jobs and How They Work
Locking pliers are used to clamp and hold a part tight so both of your hands stay free. They also grip stuck, rounded or awkward fasteners that normal pliers and wrenches slip on. A lever lock keeps the jaws closed without you squeezing, which is why they work as a small portable clamp.
WORKPRO W031573Best overall
IRWIN 1602L3Precision narrow-space reach
DURATECH Chrome-finished curved jawThe short version: what locking pliers do
Locking pliers do one thing very well: they grab a part and stay grabbed. You set the jaws, squeeze the handles until the mechanism snaps over center, and the tool holds on by itself. That frees your hands to drill, saw, weld, or turn something else.
Most people use them in four ways: clamping, holding, gripping a damaged fastener, and pulling or twisting. The sections below cover each, plus how the lock works and where these pliers are the wrong choice.
How locking pliers work
Locking pliers use a toggle action. When you squeeze the handles, a linkage inside moves past its center point and wedges itself in place. At that point the jaws are locked closed, and the force on the work is much higher than a tired hand could hold with ordinary pliers.
An adjustment screw in the end of one handle sets how far the jaws close before the lock engages. Turn it in for a tighter grip on thin material, or out for thicker stock. Many models also have a trigger or release lever that opens the lock with one hand.
- Adjustment screw: sets jaw opening and clamping pressure for the thickness of your work.
- Release trigger: unlocks the jaws, often with one hand.
- Jaw teeth: bite into the surface so the part does not rotate or slide.
- Handles: the lever that builds the clamping force. Anti-slip grips help when your hands are oily.
The most common jobs
Clamping is the everyday use. Locking pliers can hold two pieces together while glue sets, hold sheet metal flat while you drill it, or keep a part steady on a bench edge. Curved jaws are good here because they grip flat stock as well as round parts.
Holding is the close cousin. A common use is holding metal parts in place for welding or brazing. Because the jaws stay closed, your hand stays away from the work. Wear welding gloves and eye protection, and remember the pliers will get hot.
Gripping a stripped or rounded nut or bolt head is another classic. The locked jaws bite into the damaged corners and let you turn a fastener that a wrench would slide off. Expect the jaws to mark the fastener, so use this for parts you plan to replace.
Pulling and twisting also come up often. People use them to pull out bent nails and staples, twist and hold wire, and turn small shafts or rods. Long nose styles reach into narrow spaces and hold small fasteners.
One more job is as a temporary handle. If a small part is too short or hot to hold, lock the pliers on and use them as an extension.
Pick the jaw shape for the job
Jaw shape decides what the pliers do best. A 7 in curved jaw is a sensible starting point for general repair, according to our best locking pliers page. Add a long nose pair when you work in tight spots. Straight jaws suit flat work.
Some sets include a locking C-clamp style. The DEKOPRO set on our page lists a 6 in locking C-clamp with a 2 in maximum jaw capacity. It is meant for reaching around rolled edges, angle iron bends and similar barriers where a standard jaw cannot sit square.
| Jaw style | Best for | Watch out for |
|---|---|---|
| Curved | Nuts, pipe, round parts, and clamping flat stock | Can mark soft or finished surfaces |
| Long nose | Narrow spaces, small fasteners, staples, thin material | Less clamping reach across wide stock |
| Straight | Flat work and sheet material | Poor grip on round parts |
| Locking C-clamp | Face frames, edges, and reaching around obstacles | More specialized, so less useful as a first pair |
Can locking pliers replace clamps?
For small jobs, yes. Locking pliers can act as a clamp for sheet metal, small wood pieces, and parts you need to hold while you work. The jaws are narrower than a bar clamp or C-clamp, so they hold a smaller area and can dent soft material.
They have limits on capacity, too. Jaw capacity is how wide the jaws can open around the work. Our page notes that only five of 25 products list it, with the highest listed at 1.6875 in. If you plan to clamp thick stock, choose a model that publishes the number rather than guessing.
For large glue-ups, wide boards, or anything needing even pressure across a long span, a proper bar clamp is the better tool.
What not to do with them
Locking pliers are strong, but they are not a do-everything tool. Using them in the wrong place can damage the work or hurt you.
If you want a general-purpose plier for everyday gripping, bending and cutting, compare options on our best pliers page. Locking pliers work best alongside them, not in place of them.
- Do not use them as a hammer or pry bar. The jaws and lock can be damaged.
- Do not use them on a fastener you want to keep in good shape if a socket or wrench fits. The teeth leave marks.
- Do not use them on live electrical wiring. Unless the tool is specifically rated for it, the handles are not insulation. Turn the power off first.
- Do not squeeze the handles near your fingers when the lock snaps shut. The jaws and the release lever are pinch points.
- Wear safety glasses when cutting wire, pulling nails, or working with anything under tension. Pieces can spring or fly off.
Features worth looking for
A few features make locking pliers easier to live with. A one-hand release trigger helps when your other hand is holding the work. An anti-slip handle helps with control. Chrome vanadium and heat-treated alloy steel are the two steel types listed most often on our page, and both are meant to resist wear under pressure.
Some models add a wire cutter near the pivot. The WORKPRO 7 in curved jaw plier on our page lists a wire cutter, trigger release and adjustment screw at 0.7 lb. The IRWIN 4 in long nose lists a 1.625 in jaw capacity and hardened teeth. Check the spec sheet for the features you actually need, since not every maker lists them.
Frequently asked questions
Are locking pliers the same as Vise-Grips?
Vise-Grip is a brand name from IRWIN. People often use it for any locking pliers, but the tool style is made by many brands.
Can locking pliers loosen a rounded bolt?
Often yes. Lock the jaws tightly on the damaged head and turn. If the bolt is rusted solid, apply penetrating oil first and expect marks on the head.
Why won't my locking pliers stay locked?
The adjustment screw is usually set too loose or too tight for the thickness of the work. Open the jaws, turn the screw a little, and try again. Worn jaws or a damaged lock may need a replacement.
Is a long nose or a curved jaw better for a first pair?
Curved jaw is the usual first pick for general repair because it grips round and flat parts. A long nose pair is a good second pair for tight spaces.