Milwaukee 4004 Operator's Manual page 12

Sharpening Procedure for Core Bits
To work effi ciently, diamond core bits must main-
tain good diamond exposure. Many factors work
together to provide the "controlled erosion" cycle of
the tool's segment to occur. When this "controlled
erosion" cycle is altered, the bit can become dull
or "glazed." Glazing becomes noticeable when
the coring feed rate slows dramatically or the bit
does not cut. Examine the bit immediately. If the
diamonds are fl ush with the metal, they are under-
exposed or "glazed."
The following steps will often correct the problem:
1. Reduce water fl ow until it becomes very muddy.
Continue using as little water as possible until
penetration increases.
2. If the bit does not open up, remove from hole.
Pour into the kerf a thick (1/4") layer of silica sand
(the coarser the better).
3. Resume drilling for approximately 3 to 5 minutes
with very little water and at a lower RPM if pos-
sible.
4. Gradually increase water fl ow to fl ush sand from
kerf.
5. Repeat as needed.
The Effects of Steel in Coring
• To self-sharpen, diamond-impregnated core bits
require interaction with an abrasive material. This
abrasive material wears away the metal composi-
tion in the segment's matrix. As this is done, sharp
diamonds are exposed and the grinding action
created by the diamonds continues.
• Embedded metal (rebar) is not an abrasive mate-
rial. It does not provide the degree of abrasiveness
required for matrix wear to occur and expose sharp
diamonds embedded in the segment's matrix.
• A high degree of exposure to embedded metal
by the bit's segments creates glazing. Glazing
prevents the bit from cutting and coring.
ACCESSORIES
WARNING
always unplug the tool before attaching or
removing accessories. Use only specifi cally
recommended accessories. Others may be
hazardous.
For a complete listing of accessories refer to your
MILWAUKEE Electric Tool catalog or go on-line
to www.milwaukeetool.com. To obtain a catalog,
contact your local distributor or a service center.
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To reduce the risk of injury,