Blastrac BMS-220 ADB Operating Manual page 19

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. 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. 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.
Saving time with extra cutting heads
The machine is supplied with one cutting head. Having additional cutting heads will save time on the job.
Insert blades into the extra cutting heads before starting a job. When the blade is dull, instead of taking the
time to replace it or sharpen it on the job, take out the cutting head and replace it with another. Or, when a
different type or size of blade is needed, you have them ready to use.
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