A header for an agricultural harvester comprising a frame , an epicyclical drive supported by the frame , the epicyclical drive including: a first rotatable wheel having a first substantially vertical rotational axis , a first disk having a first eccentric axis rotatable about the first substantially vertical rotational axis , the first substantially vertical rotational axis being parallel to the first eccentric axis , wherein operation of the epicyclical drive results in oscillating motion of the first disk in a direction transverse to the first substantially vertical rotational axis ; a first cutter bar directly connected to the first disk , a second rotatable wheel having a second substantially vertical rotational axis , a second disk having a second eccentric axis rotatable about the second substantially vertical rotational axis , the second substantially vertical rotational axis being parallel to the second eccentric axis , wherein operation of the epicyclical drive results in oscillating motion of the second disk in a direction transverse to the second substantially vertical rotational axis ; a second cutter bar directly connected to the second disk wherein the first cutter bar extends in a direction substantially transverse to the first substantially vertical rotational axis and the second cutter bar extends in a direction substantially transverse to the second substantially vertical rotational axis , characterized in that the oscillating motion of the first disk is in line with a longitudinal axis of the first cutter bar , and and that the oscillating motion of the second disk is in line with a longitudinal axis of the second cutter bar . a first rotatable wheel having a first substantially vertical rotational axis , a first disk having a first eccentric axis rotatable about the first substantially vertical rotational axis , the first substantially vertical rotational axis being parallel to the first eccentric axis , wherein operation of the epicyclical drive results in oscillating motion of the first disk in a direction transverse to the first substantially vertical rotational axis ; a first cutter bar directly connected to the first disk , a second rotatable wheel having a second substantially vertical rotational axis , a second disk having a second eccentric axis rotatable about the second substantially vertical rotational axis , the second substantially vertical rotational axis being parallel to the second eccentric axis , wherein operation of the epicyclical drive results in oscillating motion of the second disk in a direction transverse to the second substantially vertical rotational axis ; a second cutter bar directly connected to the second disk wherein the first cutter bar extends in a direction substantially transverse to the first substantially vertical rotational axis and the second cutter bar extends in a direction substantially transverse to the second substantially vertical rotational axis , characterized in that the oscillating motion of the first disk is in line with a longitudinal axis of the first cutter bar , and and that the oscillating motion of the second disk is in line with a longitudinal axis of the second cutter bar . <EOS>