12 MAINTENANCE
READ THE SAFETY INSTRUCTIONS
CAREFULLY
12.1 SHARPENING THE CUTTING KNIVES
The cutting angle of factory-new cutting knives is 30.5°. This is he optimum angle which
should always be used when re-sharpening the knives. A smaller angle will result in chipping
in the knife edges, while a greater angle will reduce the knife edge's clearing angle causing a
reduction in the ability of the knives to draw in the material.
Note that the cutting knives must not be allowed to heat up during the sharpening process as
the knives will otherwise loose the hardness acquired by their heat-treatment. The knives
should therefore be sharpened solely by grinding. When grinding, care should also be taken
to sharpen all knives by equal amounts, so that the overall balance of the knife flange is
retained.
As a rule, there is normally no need to sharpen the bed knives. Their cutting edges may,
however, be rounded off if the intaken material includes substances that are harder than
wood (nails, sand etc.). A blunted bed knife can be re-sharpened with e.g. an electric hand-
grinding machine. In the main, the bed knives should
remain maintenance-free.
DISC SAFETY LOCK
All JUNKKARI chippers are fitted with a safety lock
forsecuring the cutting flange immobile while carrying
out any maintenance work on the cutting knives.
12.2 LUBRICATION
Following lubrication operations should be carried out at the intervals of the cumulative
operating hours given in the tables.
Disc shaft bearings (2 ea):
Remove the bearing upper housing and fill in
with lubricating grease
50 h
Feed mechanism bearings (2 ea)
50 h
Hydraulic system (HJ 10 SL)
First oil change
10h
Subsequent oil changes
50h
First oil filter changes
50h
Subsequent oil filter changes
50h
Hydraulic oil:
MOBIL DTE 13 or equivalent
System oil capacity:
28 litres (6.2 gal Imp., 7.4 gal US)
CUTTING KNIFE
C
15