Cutting Height; Down Pressure - Jacobsen LF550-H-T4F Safety, Operation And Maintenance Manual

10.9 CUTTING HEIGHT _________________________________________________________

Note: Always make the reel-to-bedknife adjustment before you adjust the height of cut. See Sections 10.7 and 10.8.
1. Lift the cutting units to the transport position. Set the
parking brake switch in the ON position, stop the
engine and remove the key from the ignition switch.
2. Set the height of cut (HOC) on the HOC gauge.
a Measure the distance between the bottom of the HOC
screw head and the gauge surface.
b Adjust the HOC screw to get the correct height then
tighten the wing nut.
3. Loosen the flange nuts on the front roller brackets to
allow the adjuster to lift or lower the roller.
4. Put the HOC gauge across the bottom of the front and
rear rollers at one end of roller.
5. Move the head of the HOC screw over the bedknife.
Rotate the adjuster knob to close the gap between the
screw head and bedknife.
Repeat Steps 4 and 5 on the opposite end of the reel.
Complete the adjustment to one end before you
adjust the opposite end.
6. Tighten the flange nuts and recheck each end.

10.10 DOWN PRESSURE_________________________________________________________

Each reel is has a down pressure spring. Down pressure
improves the cutting quality by contact between the reel
and ground. Check and adjust the down pressure any
time the HOC is changed or to improve the cut for the
best performance.
1. Lift the reels to the transport position. Put the
adjustment pin in 4th hole from ball joint. Lower the
reels on a flat surface before you measure the
down pressure.
2. Set the distance between the ball joint center and
the rod pin center to 8-15/16 in. ± 1/16 in. (22.7 mm
± 0.2 cm). To adjust the length, loosen the jam nut
and rotate the rod into or out of the ball joint.
3. Measure length of spring as shown on all 5 reels.
Record the shortest spring dimension. Adjust the
ball joint to get the other springs to the same dimension ± 1/16 in. (0.2 cm). The rod pin must be horizontal, then
tighten the jam nut.
4. To adjust the down pressure, move the adjustment pin one hole toward the spring to increase the down pressure
on the rear roller. Move the adjustment pin one hole away from the spring to decrease the down pressure on the
rear roller.
Adjuster
Knob
Flange
Nut
HOC
Gauge
8-15/16 in.
(22.7 cm)
Rod
Rod
Pin
ADJUSTMENTS 10
HOC
HOC
Screw
Wing
Nut
Bedknife
Ball
Joint
Jam
Nut
Adjustment
Pin
70