N.J. Phillips 25/50ml return spring and lever screw

Details

These are the two parts that decide whether the trigger comes back on its own. The return spring resets the mechanism after each stroke; the lever screw is the pivot the handle works around. When the spring weakens or the screw wears or works loose, the symptom is the same from the operator's end: a trigger that feels sloppy, hangs back, or needs a nudge before the next dose. On a big run that is dozens of extra hand movements and a lot of frustration. Both parts fit the 25ml and 50ml applicators. Neither is expensive and neither is the sort of thing you want to discover is worn on the morning you have four hundred head to get through. The sensible approach is to keep a set in the box alongside your spare o-rings, and to check the lever screw for tightness when you strip the applicator down for cleaning. Cold makes a tired spring behave much worse than it does in July, so if the trigger is already lazy in the fall, replace it before winter. Clean the applicator through after every use and lubricate the mechanism as the manufacturer directs.