An automatic lubrication system (201, 401) comprising - a lubricant container (230, 330, 430) supplying a lubricant, preferably grease, to a plurality of lubricant feeder units, - a plurality of lubricant feeder units, which lubricant feeder units supply the lubricant to a work device, wherein each lubricant feeder unit comprises - a piston chamber allowing a piston to reciprocate, - a piston to supply the lubricant to the work device and which piston separates a working pressure inlet and a lubricant inlet, - a lubricant inlet for supplying lubricant from the lubricant container (230, 330, 430) to the piston chamber, - a valve member, preferably a check valve, allowing the lubricant to flow out from the piston chamber and blocking the flow back to the piston chamber, - a working pressure inlet actuating the piston by supplying pressure to the piston from the work device when the work device is used, - a body of the lubricant feeder unit, the body is arranged of a uniform piece, preferably steel, and wherein the working pressure inlet, lubricant inlet and piston chamber are grooves in the body, characterized in that each lubricant feeder unit comprises - a support for an adjustment screw, the support is arranged to hold the adjustment screw, - an adjustment screw for adjusting the stroke of the piston, the adjustment screw is arranged to face an end of the piston, and - a spring configured to return the piston to its starting position, the spring is arranged between the piston and the support. - a lubricant container (230, 330, 430) supplying a lubricant, preferably grease, to a plurality of lubricant feeder units, - a plurality of lubricant feeder units, which lubricant feeder units supply the lubricant to a work device, wherein each lubricant feeder unit comprises - a piston chamber allowing a piston to reciprocate, - a piston to supply the lubricant to the work device and which piston separates a working pressure inlet and a lubricant inlet, - a lubricant inlet for supplying lubricant from the lubricant container (230, 330, 430) to the piston chamber, - a valve member, preferably a check valve, allowing the lubricant to flow out from the piston chamber and blocking the flow back to the piston chamber, - a working pressure inlet actuating the piston by supplying pressure to the piston from the work device when the work device is used, - a body of the lubricant feeder unit, the body is arranged of a uniform piece, preferably steel, and wherein the working pressure inlet, lubricant inlet and piston chamber are grooves in the body, characterized in that each lubricant feeder unit comprises - a support for an adjustment screw, the support is arranged to hold the adjustment screw, - an adjustment screw for adjusting the stroke of the piston, the adjustment screw is arranged to face an end of the piston, and - a spring configured to return the piston to its starting position, the spring is arranged between the piston and the support. - a piston chamber allowing a piston to reciprocate, - a piston to supply the lubricant to the work device and which piston separates a working pressure inlet and a lubricant inlet, - a lubricant inlet for supplying lubricant from the lubricant container (230, 330, 430) to the piston chamber, - a valve member, preferably a check valve, allowing the lubricant to flow out from the piston chamber and blocking the flow back to the piston chamber, - a working pressure inlet actuating the piston by supplying pressure to the piston from the work device when the work device is used, - a body of the lubricant feeder unit, the body is arranged of a uniform piece, preferably steel, and wherein the working pressure inlet, lubricant inlet and piston chamber are grooves in the body, characterized in that each lubricant feeder unit comprises - a support for an adjustment screw, the support is arranged to hold the adjustment screw, - an adjustment screw for adjusting the stroke of the piston, the adjustment screw is arranged to face an end of the piston, and - a spring configured to return the piston to its starting position, the spring is arranged between the piston and the support.