6 reel to bedknife adjustment, 7reel end play adjustment, 8 backlapping procedure – National Mower HYDRO HYD70OM-8/99 User Manual
Page 15
NATIONAL HYDRO 70" TRIPLEX
®
15
7.6 REEL TO BEDKNIFE
ADJUSTMENT
The reel is adjusted to a fixed position bedknife.
This makes a more rugged and stable frame retaining
adjustment longer.
To adjust the reel to bedknife contact, turn the
hex adjuster on each side of the reel down. Proceed
slowly and do not over adjust - about 1/8th of a turn on
each side. Do not over tighten. A too tight reel will wear
much faster. The reel should wipe or lightly touch the
bedknife. By using paper strips held between reel and
bedknife, check to see that blades are cutting the paper
all the way across.
Use heavy gloves and be careful
blades are sharp!
7.7REEL END PLAY ADJUSTMENT
As the reel is used, normal wear of the reel
bearings will cause end play. This condition could cause
uneven wear to moving parts and uneven cutting of turf.
Test for end play periodically by trying to move
the reel from side to side in the frame. If there is any
movement, adjust by loosening the locknut on the
adjustment body, which is located on the inside right
end of the reels and turn adjustment bolt in a half turn or
less. Do not overtighten as it would cause excessive
bearing wear. Test again for end play, if reel is rotating
freely and end play can not be detected, retighten the
locking nut on adjustment bolt.
LOCKNUT
& SCREW
7.8 BACKLAPPING PROCEDURE
Back lapping is a very important step in
maintaining sharp reel blades on the rear and wing
mowers.
Many types of compounds are available for
lapping. However, we recommend a good pre- mixed
water soluble compound such as Pinhigh. Prices, grit
ranges and ordering information are available by calling
a toll free phone number 1-800-422-4748. Pre-mixed
compound saves the time required to mix, eliminates the
waste of abrasive, rinses off easily with water and is
available in all grit ranges from coarse to extra fine.
This procedure should be performed when the
reel blades and bed knife become slightly rounded and
the grass is not cut cleanly with only a slight bed- knife
adjustment. After grinding the bedknife and reels,
backlapping should be done to establish a perfect match
between the bedknife and reel blades.
1. Clean cutting units of any foreign debris and
disengage reel clutch.
2. Make sure to adjust the bedknife to the reel so that
the bedknife is level with the reel and light contact is
maintained.
3. Reels must be run in a reverse direction to be
lapped. Remove exterior guards as needed. Attach
a back lapping machine (not supplied by National
Mower) to one of the outside reel stub shafts of the
front two cutting units, following the instructions
furnished by the backlapping machine
manufacturer.
Some back lapping machines may not rotate all
three cutting units simultaneously. If this occurs
back the reel adjustment off or disconnect the
remaining two cutting units and concentrate on
one cutting unit at a time.
4. With reels running, and concentrating on one reel,
apply the lapping compound using a 2" or 3" wide
brush. Apply the compound evenly to the mowing
blades. Adjustment of the reel to bedknife may be
required, relap as necessary.
Be extremely careful not to let the brush,
your fingers or your clothing get caught
in the reels. Use approved safety
glasses to protect eyes from flying
particles and abrasives.
NOTE