Weight Vs. Sharpness; Cutting Head Angle; Steep Cutting Head Angle; Swivel Head - National 5600 Instruction Manual

CUTTING HEAD & BLADES

WEIGHT VS. SHARPNESS

The most common way to compensate for a dull blade is to add more weight and raise the blade angle
(see re-scrape setting). Weight allows dull blades to be used to a point. Weight also causes blades to dull
and break easier. Blades of any thickness tend to catch cracks and expansion joints and will bend or
break the blade if set at a high angle. For best results, run a small ditching blade at a low angle to
identify as many cracks and joints as possible. If blades are breaking, you are misunderstanding the
conditions.

CUTTING HEAD ANGLE

Set the cutting head angle to where the material comes up the easiest. The lowest is usually the best.

STEEP CUTTING HEAD ANGLE

A steep angle is only used for re-scraping. The slide plate has to be raised so the bottom of the slide
plate is higher or even with the bottom of the guide channels (See Figure A). Not raising the slide plate
when operating the machine at a steep angle will cause the machine to jump and buck. It does not give
the operator a clear vision of the cutting head and it raises the machine to operate at a unsafe operating
height (See Figure B). Failure to raise the slide plate could cause machine damage and/or bodily injury.

SWIVEL HEAD

The swivel head keeps the blade in contact with the floor even when the floor is uneven. When using a
flat blade, by swiveling the head over 180° allows another sharp edge on the blade without having to
replace the blade.
Slide plate is raised
Figure A
Correct slide plate setting with a steep
cutting head angle.

CUTTING HEAD INSERTION

With machine off, insert desired cutting head into cutting head holder. Secure with cutting head clip.
CAUTION: Watch out for obstructions in the floor (ie. expansion joints, nails, bolts, receptacles).
They will break blades.
Slide plate is not raised
Incorrect slide plate setting with a steep
cutting head angle.
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Figure B