In a cutter bar having a upper and lower knife guards in cooperating pairs mounted on a support bar where each guard includes at least one point extending forwardly to define a channel therebetween in which the knife reciprocates, the upper knife guards are attached to an upper surface of the support bar by a compressible resilient pad between an under surface of the upper knife guard and the upper surface of the support bar, at least one hold down screw fastener engaged between the upper knife guard and the support bar which holds the upper knife guard on to the resilient pad and forms a fulcrum and at least one adjustment screw between the upper knife guard and the support bar behind the screw fastener so that adjustment of the screw increases an amount of compression of the compressible resilient pad.
