New Holland 499 Operator's Manual page 86

Usually when the guard's alignment needs to be
adjusted it is because the cutter bar and not the
guards are bent. A homemade guard straightening
tool, 1, or heavy hammer can be used to align the
guards.
Use a new knife or straight knife with little wear as a
gauge to check and adjust the alignment. Start at the
outside of the cutter bar. Insert the knife assembly in
the guards and check the alignment as the knife is
being installed. Bend any high guards down as the
knife is being installed. Bend any low guards up after
the knife is installed. If a hammer is used to bend the
guards, be sure to hit the solid surface in front of the
knife section to avoid breaking the lip.
In case of severe damage to the cutter bar, remove
all guards. Stretch a string, 1, across the width of the
cutter bar to use as a guide in straightening the cutter
bar. Support the string on the same six spacer, 2, at
each end of the cutter bar. The cutter bar should be
straight for the full width. A small, gradual, bow, less
than 3 mm (1/8"), down in the center is acceptable.
The cutter bar can resemble a smile, not a frown.
SECTION 4 - MAINTENANCE
1
4889-14/4889-15
4-26
35
1
2
36