Auto & Shop InformationLesson 15 of 17
Gripping and Clamping Tools
Plier types, locking pliers, vises and clamps.
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Every tool in this lesson exists so that your hands can stop being the thing that holds the work. That frees both hands for the tool and, more importantly, keeps the work from moving when the tool bites.
Pliers
| Pliers | For | Recognized by |
|---|---|---|
| Slip-joint | general gripping, two jaw positions | a pivot that shifts |
| Tongue-and-groove (water pump) | large, round objects; many jaw positions | long angled jaws, a grooved slot |
| Needle-nose | reaching into small spaces, bending wire | long tapered jaws |
| Diagonal cutting (side cutters) | cutting wire and small fasteners | angled cutting jaws, no flat grip |
| Locking (vise grip) | clamping onto something and staying there | an adjusting screw and a release lever |
| Lineman's | electrical work; gripping, twisting and cutting | square nose with a cutter behind it |
| Snap ring | fitting and removing retaining rings | fine tips, sometimes reversible |
Diagonal cutters are the odd one out. They have no flat gripping surface, because their jaws come together in a cutting edge. If a question asks which pliers cannot hold a workpiece, that is the answer.
Tongue-and-groove pliers open wide and stay parallel, which is what suits them to pipe, large nuts and round work. The groove holds the setting so the jaws do not close under load.
Locking pliers clamp and release themselves. An adjusting screw sets the jaw opening and the over-center handle locks them shut with a great deal of force, which is why they double as a clamp, a temporary handle and a way to grip a rounded-off bolt.
Pliers are not a substitute for a wrench, and this is the practice question that comes up most in this topic. A plier jaw grips two flats loosely and its serrated teeth bite into the corners, which is exactly how a hex fastener becomes round. Once rounded, a nut cannot be turned by anything short of a bolt extractor or a cutting torch, so a moment saved becomes an hour lost. The same goes for locking pliers, with the added problem that they grip hard enough to crush thin-walled parts.
Vises
| Vise | For |
|---|---|
| Bench vise or machinist's vise | general metalwork; jaws with serrated faces |
| Woodworking vise | wood; flat wooden or lined jaws, mounted flush |
| Drill press vise | holding work on a drill press table |
| Pipe vise | round stock; a V or chain grip |
A bench vise's jaws are serrated to grip hard, and they will mark anything soft. Soft jaws or jaw caps - aluminum, copper, brass, or lead - are fitted when the work must not be marked, which is the question here.
Clamp the work near the jaws. A long piece held only at the bottom will vibrate and chatter under a file or a saw, and the cut will wander.
Clamps
| Clamp | For |
|---|---|
| C-clamp | general clamping; a screw in a C-shaped frame |
| Bar clamp | wide work; a sliding jaw on a bar |
| Pipe clamp | very wide work; the same idea on a length of pipe |
| Spring clamp | light, quick holding |
| Hand screw | wooden jaws that can be set non-parallel |
| Band or strap clamp | pulling a frame or a round assembly together |
| Quick-grip clamp | one-handed clamping with a trigger |
Use a scrap block between the clamp and the work so the pressure spreads and the jaw does not dent the surface. That is both practice and a question.
Clamp before you cut, drill or grind. An unclamped piece caught by a tool becomes a projectile, and a piece of sheet metal caught by a drill bit becomes a spinning blade.
Know it by sight
| Item | How to recognize it |
|---|---|
| Slip joint pliers | a pivot that shifts between two positions; short jaws with a gripping section |
| Adjustable joint pliers (Channellock) | long handles and angled jaws with many groove positions - the brand name Channellock is often used for them |
| Needle nose pliers | long, thin, tapered jaws |
| Lineman pliers | heavy, with a blunt square nose and a cutter just behind it |
| Locking pliers (Vise-Grips) | an adjusting screw in the end of one handle and a release lever in the other |
| Pincers | rounded jaws that meet in a flat edge at the end, for pulling nails |
| Bench vise | a heavy iron vise bolted to a bench, with serrated jaws |
| Pipe vise | a V-shaped or chain grip for round stock |
| Handscrew | two long wooden jaws worked by two threaded spindles |
| C clamp | a C-shaped frame with a screw through one end |
| Bar clamp | a sliding jaw on a long flat bar |
| Spring clamp | a spring-loaded clip with plastic-tipped jaws, squeezed open by hand |
What you can skip
Across the 59 questions on this topic in our bank:
- Specialty clamps - toggle, miter and vacuum clamps - never appear; a corner clamp comes up once.
- Brand names as knowledge. Channellock and Vise-Grip appear only as labels on the picture questions. Know the generic names; the brand is printed beside them.
Where people lose points
Using pliers as a wrench. They round the fastener.
Thinking diagonal cutters can grip. They only cut.
Clamping finished work in bare vise jaws. Soft jaws exist for that.
Clamping without a protective block. The jaw marks the work.
Confusing slip-joint with tongue-and-groove. Two positions against many.
Holding work by hand at a drill press. Clamp it.
Work one in under a minute
A bolt head has been rounded off and a wrench no longer grips it. Which tool in this lesson offers the best chance of removing it, and why does it work when a wrench does not?
Locking pliers.
A wrench works by contacting flat faces. Once the corners are rounded, there is nothing flat left for the wrench to push against, so it slips no matter how hard it is held.
Locking pliers do not depend on flats. The adjusting screw sets the jaws just under the size of what is left of the head, and the over-center handle forces them closed with far more clamping pressure than a hand can supply.
The jaws' serrations bite into whatever shape remains, and the grip is mechanical rather than a matter of holding pressure, which leaves both hands free to turn.
This is also the reason the Callout warns about pliers on good fasteners. The tool that saves a rounded bolt is the tool that rounds them in the first place.
Where this leads
Holding the work is what the drilling and finishing lessons assume, and the over-center action in locking pliers is the lever lesson again.
Related lessonsReference
- Finishing Tools - the work these tools hold still
- Drilling and Boring Tools - why clamping is a safety issue
- Levers - the handle that multiplies grip
- Shop Safety and Practice - securing the work
Practice this topic
Check that this lesson stuck. Answer questions on gripping and clamping tools only, and see the right answer and why after each one.
Practice Gripping and Clamping Tools questions