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Lineman's pliers, showing wire cutter below the gripping jaws
|Other names||combination pliers, Kleins (US/CAN), nines|
Lineman's, linesman's (US English) or combination pliers or linesman pliers (Canadian English) are a type of pliers used by electricians and other tradesmen primarily for gripping, twisting, bending and cutting wire and cable. Linemen's pliers owe their effectiveness to their plier design, which multiplies force through leverage. Lineman's pliers have a gripping joint at their snub nose and cutting edge in their craw. Some versions include either an additional gripping or crimping device at the crux of the handle side of the pliers' joint. Lineman's pliers typically are machined from forged steel and the two handles precisely joined with a heavy-duty rivet that maintains the pliers' accuracy even after repeated use under extreme force on heavy-gauge wire. Lineman's pliers usually have grips for better handling than bare metal handles; the grips may also provide insulation for protection against electric shock when working with live circuits, although most models are marked as not listed for such use. Some pliers are certified to withstand a specified voltage, e.g. 1000V.
Like most hand tools the durability and useful working life of linemen's pliers vary greatly according to load, frequency of use and the specific design and quality of the tool. Linemen's pliers may be forged out of alloyed or unalloyed tool steel. For basic quality pliers unalloyed tool steel with a relatively low carbon content of 0.45% may be used. Top-quality pliers are typically made from higher carbon tool steel and alloyed with elements such as chrome, vanadium and molybdenum. In addition to being suitable cutting soft copper and aluminum, pliers may be specifically designed for cutting hardened wire, such as piano wire or nails, by induction hardening of the cutting edges.
Lineman's pliers cut, bend, and may be used to strip wire insulation or cable jackets. As with most pliers and scissors or shears, lineman's pliers apply most force closest to the pivot-point of the two handles so, for larger materials, the closer the wire or cable is to the joint or 'craw' of the pliers, the easier and cleaner the cut will be. The closer the cutting edge is to the pivot axis, the greater the cutting force.
Bending and straightening
Lineman's pliers can be used to bend or straighten heavy-gauge solid wire or sheet metal components, especially in cases where smaller pliers don't offer enough mechanical advantage. The square nose and flat side of Lineman pliars is particularly useful for creating accurate right angle bends.
Cutting metal-clad (MC) cable
A rotosplit is the ideal tool for this job, but lineman's pliers can be used to first 'crack' the spiral casing of the cable by bending it sharply, partially exposing the insulated wires, inside. This creates a place for the pliers to gain purchase, and, with the application of strong force with two hands, they will cut the cable. To strip the cable, saw through one wrap of the spiral metal casing using a metal-cutting saw blade (for example, on a hack saw or powered reciprocating saw) and then use two pliers to twist the casing sharply and break apart the sections on either side of the saw cut. If no saw or rotosplit is available, it is possible (though laborious) to use lineman's pliers to grasp the end of the cable and unwind 12 inches of stiffly-spiralled aluminum to expose the wire inside.
The most common application of the lineman's pliers in gripping is to twist bare (stripped) wires together, to form a common electrical connection between the wires (wire nuts can be used to enhance this electrical connection and guard against corrosion of the contact-points between wires, as well as to insulate the bared wire ends and provide additional mechanical 'locking' of the junction). The gripping action of lineman's pliers is also used to pull fish-tape ends in a long (high-friction) wire run through conduit, to crimp ductile metals, and to pull nails and other fasteners.
Lineman's pliers are similar to needle-nose pliers: both tools share a typically solid, machined forged steel construction, durable pivot, gripping nose and cutting craw. The main differences are that the slender nose of the needle-nose pliers enable it to form small diameter bends, and position or support items in awkward places. Needle-nose pliers typically have a lower handle/nose length ratio, reducing the force that can be exerted at the tip. Also, needle-nose pliers tend be available in smaller sizes (for electronics applications, they may be found as small as 1/10 scale of the full-size version).
Lineman's pliers may be used to cut steel screws up to #10, and virtually any dry-wall screw. Although, unlike some multi-purpose wire-stripping pliers, lineman's pliers will not always maintain a clean thread-continuity after the cutting, drywall screws typically will still function in drywall or soft woods such as those used in light-frame construction; driving the screw in reverse with moderate pressure will 'drill' a starter-hole, allowing the remaining threads of a cut screw to engage and draw the screw in normally. A machine screw cut by linemans' pliers may function properly about 60% of the time, threading a nut close to the head of the screw assists by chasing the threads when the nut is removed allowing the machine screw to be used.
Lineman's pliers sometimes include an integrated crimping device in the craw of the handle side of the pliers' joint. The nose-end grippers of lineman's pliers are designed to come about 1/16" short of positive contact, when the pliers are fully closed. The pliers' gripping end may be used to squeeze soft metal flat, and function well as a crimper in some applications.
Lineman's pliers have a tapered nose suitable for reaming the rough edge of a 1/2" or larger conduit, or cleaning sharp metal from the inside of a standard metal knock-out in an electrical enclosure such as a junction box or breaker panel. Some brands manufacture pliers (i.e. Ideal) with a narrower jaw, suitable for reaming smaller conduit.
Professional lineman's pliers are quite rugged and, though not rated for striking, are quite often used to sink (but not set) concrete inserts, pound nails, or chip small bits of concrete—they are sometimes nicknamed electrician's hammer.
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