Serrated or Smooth Jaws? Choosing Compact Pliers for Small Nuts and Pipes

Serrated jaws bite into the part, which helps on round pipe and on worn or rounded fasteners. The cost is marks: teeth can scar chrome, brass, plated fittings and anything soft. Smooth jaws spread the grip over a flat face, which is kinder to finished surfaces but bites less on round, slippery stock.

KNIPEX sells both styles at the 100mm pocket size. The Cobra XS (87 00 100) has serrated jaws. The Pliers Wrench XS (86 04 100) has smooth jaws.

At full size, the 180mm KNIPEX Pliers Wrench (86 03 180) has smooth, parallel jaws. KNIPEX says it works directly on chrome and plated fittings and grips nuts up to 40mm (1-1/2 in.).

Check capacity against your largest regular job. KNIPEX lists the 100mm Cobra XS as gripping nuts up to about 24mm and pipes up to about 28mm.

A longer tool mostly adds leverage, not always capacity. The 125mm KNIPEX Cobra 125 (87 01 125) is listed with a pipe capacity of 1-1/16 in. (about 27mm), no larger than the XS, but its longer handles make it easier to apply force. For stuck or large fasteners, a full-size tool is the right choice. A pocket tool's short handles limit how much force you can apply.

The Cobra XS uses KNIPEX's push-button adjustment, which KNIPEX describes as self-locking. Whatever you buy, set the jaws snugly on the part before turning. A loose grip is what rounds off nuts. Where a correctly sized wrench fits, it's usually still the gentler choice for a nut.

Match the size to your largest nut. KNIPEX lists the 180mm (7-1/4 in.) Pliers Wrench 86 03 180 for nuts up to 40mm (1-1/2 in.), with 15 adjustment positions and a push button to set the jaws on the nut. The 150mm (6 in.) model is listed on Amazon for nuts up to 1 in., and the 100mm XS is the pocket size. KNIPEX also makes 125mm, 250mm and 300mm versions.

The handle changes the part number, not the jaws: KNIPEX sells the 180mm size with plastic-coated, multi-component or comfort grips. KNIPEX also sells a five-piece pliers wrench set in a foam tray, if you want several sizes at once.

For most home kits, the 180mm size covers faucet nuts and common bolts. Add a serrated tool such as the Cobra for round pipe.

Tools for work near live electrical circuits are sold as insulated, voltage-rated tools and are marked that way. The standard Cobra XS is not one of them. If your work involves electricity, buy a tool that's explicitly rated for it, not a general-purpose pliers.

• Worth buying: you regularly deal with small fittings in tight spaces, or you want a capable gripping tool in a pocket, bag or car kit.
• Skip a pocket tool if most of your jobs involve large or seized fasteners. Its short handles won't give you enough leverage.
• What you have may be enough: if a full-size adjustable wrench and slip-joint pliers already handle your jobs, a 100mm tool mainly adds portability, not new capability.