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6— reel to bedknife adjustment, 7—reel end play adjustment, 8— backlapping procedure – National Mower HYDRO HYD70OM-8/99 User Manual

Page 15

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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!

7.7—REEL 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

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