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The deepest throat on this shelf — 7.8 in

HEIHAK 06231043, 18 in, 3-pack

Three big locking clamps that publish both the figures that matter — a 7.8 in throat and a 6.3 in opening, the deepest and widest in this hub.

Three HEIHAK 18 inch locking C-clamps with swivel pads

HEIHAK 06231043, 18 in, 3-pack

Three big locking clamps that publish both the figures that matter — a 7.8 in throat and a 6.3 in opening, the deepest and widest in this hub.

Amazon reference
B0B4V3WN28
EAN
0755621348443
  • A 7.8 in throat depth, more than twice the next deepest clamp on this shelf
  • A 6.3 in maximum opening, which takes stacked plate or heavy box section
  • An 18 in plier is heavy and awkward on small work — these are not detail clamps

Best for: Clamping a plate or a frame well in from the edge, where a short-throat clamp cannot reach the seam

≈ $31
Check price on Amazon

Specifications

Amazon reference
B0B4V3WN28
EAN
0755621348443

The two numbers on this listing are the two that decide whether a clamp can be used at all: a throat depth of 7.8 inches and a maximum opening of 6.3. On this shelf the next deepest throat is 3-1/2 in, which means these reach more than twice as far in from the edge of the work.

That is the whole case for an 18-inch plier. A seam in the middle of a plate, a joint behind a flange, a frame whose corner is set back from the open side — all of them defeat a short clamp and none of them defeats this one. Two swivel pads per clamp let the jaws sit flat on a face that is not square to them, and the quick-release lever means repositioning does not mean unwinding the screw.

The limits are the obvious ones. An 18-inch locking plier is heavy, long, and clumsy on anything small — the ten- and eleven-inch clamps on this shelf exist for that. No clamping force is published, which is true of every clamp here. And the fifth bullet, in its entirety, reads “C-calmp for woodworking”.

Availability

Read on the day this page was built: $31 at the American Amazon shop.

Read from Keepa on the day this page was last revised; stock and price both move without notice.

Prices quoted in this text were read on 2026-10-07. The live price is at the top of the page.

The questions welders ask

Why does a deep throat matter on a welding clamp?

Because a seam is rarely at the edge. A clamp with a 3-1/2 in throat can only reach three and a half inches in from the nearest open side; past that it simply does not fit over the work. At 7.8 in these reach the middle of an eight-inch plate or across a box section with the flange in the way, which is the case that otherwise means magnets and hope. This hub’s buying tip is to clamp mechanically before running the bead, and reach is what decides whether you can.

What do swivel pads do?

They let the jaw face sit flat on something that is not flat. A fixed pad on a tapered or angled surface touches at one edge, point-loads it and slides; a swivel pad rotates to the surface and spreads the load. On welding work, where faces are often angled and sometimes hot, that is the difference between a clamp that holds and one that walks off as the metal moves.

More clamps & vices

  • Set of nickel-plated 6 inch locking C-clamp pliers

    Biugaaufai 6 Inch locking C-clamp set

    A set of 6-inch locking clamps whose own listing cannot agree on how many are in the box.

    Amazon reference
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    EAN
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    • Several clamps in one purchase, which is how a frame actually gets held
    • Nickel-plated alloy steel, stated
    • The title says "6 Pack" and the first bullet says "four 6-inch C-Clamp pliers" — the quantity is not settled anywhere on the page

    Best for: Small work and body panels, where several modest clamps beat one large one

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  • KAKA Industrial cast iron 90 degree angle clamp holding two square tubes

    KAKA INDUSTRIAL AC-100

    The only clamp on this shelf that holds a right angle on its own, bolted to a bench — with a copper-plated screw so spatter does not weld to the thread.

    Amazon reference
    B0159ZUQ22
    EAN
    0745369240840
    • Holds a true 90 degrees mechanically, which is what this hub’s buying tip says magnets cannot do
    • Publishes all three jaw dimensions — 4 in opening, 2-1/4 in height, 3-1/2 in width
    • The listing calls 26 lb a "lightweight design" in the same sentence that publishes the figure

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  • Monster & Master V-pad locking pipe clamp on a square tube

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    A V-jaw clamp that publishes the tube sizes it holds and states plainly that it takes square section as well as round.

    Amazon reference
    B08LD3GBZS
    EAN
    6972748327999
    • Publishes the sizes it holds — 1, 2 and 3 in — rather than a single capacity range
    • States that the V-jaws take plain round AND square tube, including mixed joints
    • A 3 in ceiling, below the 6.3 in opening of the large clamps on this shelf

    Best for: Frames mixing round and square tube, where one clamp has to seat on both

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Elsewhere in the workroom

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    Baer Thread cutting set M3–M12, 30 pieces

    The same range with the matching drills in the box — no chart, no arithmetic, no broken taps.

    Range
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    Quantity
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    Material
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    Includes
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    Amazon reference
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    EAN
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    • €138 — twice the set without drills

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  • Bosch Accessories X-LOCK 5-piece set, Ø 125 mm, product photograph

    Bosch Accessories X-LOCK 5-piece set, Ø 125 mm

    X-LOCK discs clip on without a wrench — provided your grinder has an X-LOCK mount.

    Diameter
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    Amazon reference
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    EAN
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    Best for: Owners of X-LOCK grinders who change discs several times a day

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  • Bosch Professional HSS-Cobalt ProBox, 19 pieces, product photograph

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    Cobalt bits, which exist for one reason: stainless steel work-hardens and ordinary HSS gives up.

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    EAN
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