AMMCO 3860 Drum & Disc Brake Lathe - Manual (Page 9)

AMMCO 3850, 3860 Brake Lathes • 3
Brake Lathes
Principal Operating Parts
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Work Light
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T-Bolt and Self-Aligning Hex Nut
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Drive Motor (not seen in drawing)
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1"Arbor
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Arbor Nut
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Power Cord
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Twin Cutter
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Feed Handwheel
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Feed Button
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Feed Engagement Lever
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Depth-of-Cut Dial
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Slide Lock Knob
Ậ
Drive Belt Assembly Cover
ậ
Power Panel (with ON/OFF Switch)
Ắ
Tool Slide
ắ
Crossfeed
Operating Instructions
Negative and Positive Rake Tooling
3850 3860
BLACK HOLDER SILVER
POSITIVE RAKE NEGATIVE
6918 BIT 6914
0.005 MIN. CUT DEPTH 0.002
Making shallow cuts of less than .005 inches
greatly reduces the effective life of a positive rake
tool bit. Shallow cutting does not transfer heat
effectively from the bit to the rotor or drum, and
reduces the life of the bit. Shallow cuts also do not
allow the bit to dig enough, and may cause the bit
to break.
A negative rake tool bit angles downward from the
tool bit holder towards the brake surface. A positive
rake tool bit angles upwards from the holder towards
the brake surface (figure 1).
Figure 1 - Negative Rake Compared to Positive Rake
Note: Do not use positive bits on negative holders
or negative bits on positive holders!
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Ả
ả
ấ
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Ậ
ẫ
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ẩ
Ẩ
ầ
ậ
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Know Your Unit
Compare this illustration with the unit before placing it
into service. Maximum performance and safety will be
obtained only when all persons using the unit are fully
trained in its parts and operation. Each user should learn
the function and location of all controls. Prevent acci-
dents and injuries by ensuring the unit is properly
installed, operated, and maintained.
Negative Rake Positive Rake
Up/Positive
Down
Negative
Tool Bit Holder Tool Bit Holder