Wahl Clipper Not Cutting Properly

By far the most common cause. A dry blade pulls hair instead of cutting it, heats up quickly and sounds harsher than usual. Put a few drops of clipper oil across the teeth with the machine running and try again - if it was dryness, the difference is immediate and obvious.

This is worth doing even if you oiled recently. Oil migrates and evaporates, and a clipper stored for months will be dry regardless of how it was put away.

Debris between the cutter and the still blade stops them meeting cleanly, which feels exactly like a dull blade. Brush the blade out, and on a detachable machine take the blade off and clear underneath - that is where it accumulates and where a brush from the outside never reaches.

Fine hair and dry skin build a felt-like layer that is easy to miss. If the blade looks clean and still pulls, take it off and look at the underside.

Alignment is the cause behind most "cuts on one side only" and "leaves lines" complaints. The cutter should sit slightly back from the tips of the still blade - not flush, not overhanging - and it should be even across the width.

If the cutter overhangs, the blade can catch skin. If it sits too far back, the clipper cuts longer than its rating and struggles through thick hair. Loosen the mounting screws, set the cutter square and slightly back, and retighten while holding the position.

Blades knocked out of alignment by being dropped are the usual story here, and the symptom appears suddenly rather than gradually - a useful clue that the blade itself is fine.

Blade tension controls how firmly the cutter is held against the still blade. Too loose and the blade chatters, cuts unevenly and sounds rattly. Too tight and it drags, overheats and loads the motor.

Tension is set by the mounting screws on a taper clipper, and by a spring on many detachable blades. If a blade has been apart for cleaning, tension is the thing most often left wrong on reassembly.

If the clipper still pulls after oiling, cleaning, aligning and setting tension, the blade is genuinely worn - or damaged, which is visible as chipped or bent teeth under good light. At that point, replacement or professional sharpening is the answer; see replacement blades for fit.

A different symptom points at the motor rather than the blade: the clipper slows badly under load, or the sound drops in pitch as soon as it touches hair, even with a fresh oiled blade. On a corded machine that can be worn brushes or a tired armature; on a cordless one it is far more often a battery no longer holding voltage under load.