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Straight answers to the questions people ask most when choosing replacement V-groove and U-groove feed rolls for a wire feeder.
A feed roll grips the welding wire and pushes it from the spool, through the wire feeder and liner, to the torch tip at a steady speed. In a typical feeder a driven roll works against a pressure roll that holds the wire in its groove.Because every inch of wire passes through it, the roll's groove shape, size and condition have a direct effect on how steadily the wire feeds and how smoothly the arc runs.
A V-groove has angled sides that grip the wire at two points. It suits hard wires such as solid mild steel and stainless steel. A U-groove has a rounded, smooth channel that holds the wire's shape without biting into it, so it suits soft wires, mainly aluminium.Using the wrong shape can slip, flatten or mark the wire. Cored wires usually need a V-groove with a knurled (toothed) surface instead of a plain one.
The groove is machined for a particular wire diameter, usually shown on the roll as a size in millimetres or inches. Choose the roll that covers the diameter printed on your wire spool.A groove that is too large lets the wire slip and feed erratically, while one that is too small can squeeze or shave the wire and clog the liner. Always match roll, liner and contact tip to the same wire diameter.
Many rolls have a different groove on each face, so one roll covers two neighbouring wire sizes. Only one groove works at a time, so make sure the size you need is the one in the working position, as shown by the markings.If you fit the roll the wrong way round for the wire in use, the grip is wrong, which can over-tension and deform the wire and cause poor feeding. Check the markings each time you change wire.
Look at the groove: a pointed V, a rounded U, or a V with fine teeth (knurling). Look also for the size markings on the face of the roll. Compare them with the wire you currently run.If the markings have worn away, measure the wire you use and check your welder's manual for the roll types and sizes it takes. If you are not sure, our team can help you identify the right one for your machine.
The common causes are a groove that does not match the wire size or type, a worn groove, tension set too low or too high, and dirt or oil on the wire or roll. A blocked or wrong-size liner, a worn contact tip or a kinked cable can also give the same symptoms.Check the roll size and side, clean the groove, reset the tension, and then work along the wire path from the feeder to the tip.