This double knife guard mounts on the cutterbar beam to hold the reciprocating knife section in position during cutting. It guides the knife sections and provides a stationary shear edge against which the moving knife cuts the crop stems. The forged construction gives the guard the strength needed to withstand impact from stones and uneven ground without bending or breaking. A worn or bent guard allows the knife to move out of alignment, causing missed cuts and increased power draw. The guard is secured to the cutterbar with bolts through its mounting holes; on reinstall, ensure the guard sits flush against the beam and tighten the bolts to the specified torque.