For special applications, manufacturers offer metal-cored wires for GMAW. These are composite electrodes comprised of a metal sheath with a powder-metal core. They are often confused with flux-cored wires, which form a slag that completely covers the weld bead face; metal-cored wires produce very little slag. A major advantage of metal-cored wires is the ability to manufacture specialized alloy compositions not easily available or producible in solid wire fore1. Modifying the composition of the powder-alloy core allows the wire manufacturer to customize wire formulations to metallurgical, compositional, or physical properties per customer demand. Horizontal-fillet welds made with metal-cored GMAW can deposit weld metal at rates up to 20 percent higher than with solid wire. Alloying elements, such as silicon, in the powder-metal core improve sidewall wetting and reduce weld-bead convexity by reducing surface tension of the molten weld pool. For this reason, flat and horizontal welds deposited with metal-cored wires have better appearance than weld metal deposited with flux cored and solid wires. Compared to solid wires, metal-cored wires also result in higher current density, for increased penetration; a wider operating window with respect to welding-process variables: better sidewall melting; and less lack of fusion.

Judging by the tools, manufacturers seem to favor the workers who want more power. The last time this magazine looked at 14.4-volt drills was in 1999, when the most powerful tool produced 330 inch-pounds of torque in the low speed setting. This time around, the top performer put out 484 inch-pounds. But that increase in power comes at the cost of some added weight. The current crop averages 5 pounds apiece, which is a half pound heavier than the models we tested in 1999. And the heaviest 14.4-volt tools outweigh some 18- and 24-volt models.

Though light in weight, Airbor magnetic drill has a powerful 1.6-hp air motor and 1,600-lb magnetic holding strength. With its extra rack, stroke length is extended to 10 1/4 in. Annular cutter capacity is up to 2 1/16 in. diam. Geared chuck adapter converts the unit to a standard drill press. The Slugger Air Force pneumatic drill, at 24 lbs, 6 1/4" high, is useful for confined area drilling. The drill''s features include a permanent magnet that turns on or off by air power, a cutter capacity of up to 1 1/16" diameter x 3/4" depth and the ability to use ShortSlugger cutters and frame cutters. These cutters'' geometry allows the operator to drill multi-layered truck frames in a single pass.

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