This cutter head mounts on the cutter bar of a grain harvester. It secures the knife section to the reciprocating drive, transferring motion from the drive mechanism to the cutting edge. The head is machined to match the original assembly's bolt pattern and thread specification, which ensures proper alignment of the knife sections along the bar. A worn or distorted head causes uneven knife registration, leading to ragged stubble and increased draft load on the drive. When replacing, clean the bar mounting face and use new hardware torqued to specification.