ASTEC Peterson 6710D, Operators Safety Manual, Page: 84 / 167

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P E R A T O R
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A F E T Y
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A N U A L
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1
WARNING
Flying material hazard:
Ensure that parts do not come loose from the
rotor.
• Check the tightness and condition of the bits
every day. Loose bolts, excess bit wear, and
distorted bit spacers increase the risk that the
bit will come off the rotor at high speed, possi-
bly hitting someone and causing serious injury.
• Do not tighten the nuts to the full rated value of
the bolts because the bolts are higher rated
than the nuts.
• Always change the bit bolts if the bolt head is
worn. Look carefully at each bit bolt when main-
taining bits.
• Do not reuse bolts, nuts, or washers.
Always reverse or replace bits that have 50% or more of
the abrasive carbide surface worn away, even if it looks
like enough bit steel remains to allow further grinding.
The bit holders are made of machinable steel and are not
designed to resist high abrasion. If these become dam-
aged, the bit cannot be re-bolted properly to the bit
holder.
Replace the bit backing plates, also called bruise plates,
and the bit spacers when they become warped or worn.
An impact wrench can cause damage by over-tighten-
ing, which can result in weakened and distorted parts.
Figure 87 shows wear patterns of the standard wood-
waste grinding bit. Other bits, such as asphalt shingle
grinding bits and knife-sharp bits, follow similar pat-
terns, but have differing shapes and wear rates.
Figure 87: Examples of Bit Wear Patterns
F03583 F03582
F03585
F03584
A
F03719
New bits. Use either side.
F03720
Used bits. Inspect soon.
F03721 F03722
REVERSE THESE BITS*.
Dimension A is 3/4 in. (2 cm)
* Notice that a trough has developed because the carbide
was undermined and has rubbed off. Without the carbide
coating, the bit base metal wears quickly.
DO NOT USE. Replace these
bits with a new bits.
UNSAFE TO USE EITHER
SIDE.
A
Asphalt Shingle Bits
Wood Waste Bits
New bits. Use either side.
Used bits. Inspect soon.
REVERSE THESE BITS*.
Dimension A is 3/4 in. (2 cm)
DO NOT USE. Replace these
bits with new bits.
UNSAFE TO USE EITHER
SIDE.