Hyundai HYCH7070 User Manual page 21

cutting disk. They are tapered out slightly to allow for a small amount of
movement in the cutting disk as it bites into the wood.
7.5.5. Make sure that all locknuts are tightened properly. Then turn the cutting disk
with a long wooden stick and check if the cutting disk rotates
freely. 7.6. Knife re-sharpening.
7.6.1. After removal, the knives should be sharpened on a surface grinder. Be
careful and wear gloves to protect hands. It is extremely important to
consistently maintain the 38 degree cutting angle for proper performance.
7.6.2. Excessive heat generated during the grinding process will damage the knives
and weaken the metal. Make sure that there is plenty of coolant used when
grinding to avoid overheat. If you are unable to re-sharpen the knives yourself,
take the knives to a professional machine shop for proper re-sharpening.
7.6.3. Normally only a slight touch up is needed. In this way your knives should last
for a long period of time.
7.7. Wear plate removal and replacement.
7.7.1. The wear plate is case-hardened and reversible. Normally the edges will last
for a long time. When the edge is rounded off, it can be reversed. The wear
plate cannot be re-sharpened as it will lose its hard edge due to being case-
hardened. When both edges are worn, the wear plate should be replaced.
7.7.1.1. Remove the feed hopper.
7.7.1.2. Remove the locknuts and bolts that attach the wear plate to the
chipper assembly and then remove the wear plate.
7.7.1.3. Install the new wear plate and secure with the bolts and locknuts.
The gap between the knife and wear plate must be adjusted
whenever the wear plate is removed.
7.8. Wear plate adjustment.
7.8.1. When the knife or wear plate is replaced, it is a must to check and set the
clearance between the knife and wear plate.
7.8.2. The clearance between the knives and wear plate should be approximately
1mm on the inside closest to the bearing and 3mm on the outside edge of the
cutting disk. Refer to the following diagrams for more details.
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