10
WARNING
To reduce the risk of injury, always
use Dymodrills in conjunction with
meter boxes. Meter Boxes provide a switch to
turn the Dymodrill motor OFF and ON and an
optimum operation range to help prevent motor
overload.
Shear Pin and Clutch
Dymodrill Nos. 4079, 4090, and 4094 contain a shear
pin to protect the gear and motor against overload.
This pin drives the spindle sleeve. If the bit binds,
the pin will shear to prevent gear and motor damage.
Extra shear pins are supplied with each Dymodrill
and can be replaced (see "Accessories" for part
numbers). It is important to check the condition of
the spindle before using the tool each time. The
spindle must be smooth without grooves or pitting.
If the spindle is not in good condition, it is possible
for the threaded spindle sleeve and the internal
spindle to weld together and seize during coring
(see "Lubricating the Spindle for Dymodrills with a
Shear Pin" in the "Maintenance" section for spindle
lubricating instructions).
Spindle Sleeve
(Shear pin models)
Threaded Spindle
(Clutch Models)
Shear Pin
Retaining Ring
(shear pin model only)
Cat. Nos. 4004-20, 4005, 4096 and 4097 feature a
friction clutch rather than a shear pin to protect the
motor and gears. If the motor overloads, the clutch will
begin to slip and the bit will stop rotating. The clutch
is factory-set and does not require adjustment. Nui
-
sance (frequent) clutch slippage should be addressed
by an authorized MILWAUKEE service center.
WARNING
To reduce the risk of injury, always
check the work area for hidden
wires before coring.
Coring Procedure
1. Select and install a bit following guidelines in
"Selecting and Installing a Core Bit".
2. Secure the rig to the work surface using one of
the methods described in "Methods for Securing
Equipment to Work Surface".
3. To switch speeds, turn off the motor and switch the
speed while the tool is coasting to a stop. Never
shift at full speed or when tool is underload or
stopped.
4. Connect the water hose
Water
Shut-Off
Valve
Gear
Shift
Lever
to the Dymodrill water
shut-off valve and to the
water supply. Make sure
the seal is watertight.
Use a standard garden
hose if you require ad-
ditional length. Set up a
water collection system.
5. If you are using a vacuum
system, read the instruc-
tions for specific setup in
"Assembling & Using a
Vacuum System".
Do not continue the following steps until the
vacuum gauge reads at least 20 inches of mer-
cury vacuum. Never operate the Dymodrill if the
gauge reads less than 20 inches (see "Methods
for Securing Equipment to Work Surface"). Always
monitor the vacuum gauge during coring. If water
collects in the vacuum pump filter jar, empty it to
prevent damage to the pump.
WARNING
To reduce the risk of injury, do not
operate the Dymorig if the gauge
reads less than 20 inches of mercury vacuum.
6. Turn the Dymodrill motor ON. Turn the water on
so it flows freely through the water shut-off valve
(see "Supply an Adequate Water Flow"). Turn
the valve clockwise to increase water flow and
counterclockwise to decrease water flow.
7. While holding the handle, slightly loosen the cradle
lock handle and slowly rotate the handle to lower
the bit into the workpiece, applying steady, even
pressure. To help reduce bit wandering, always
use a light load to start the hole and wait for the tip
of the bit to penetrate the work surface completely
before increasing the load.
8. Use sufficient pressure so the bit cuts constantly.
Use the ammeter on the meter box as a guide for
proper pressure.
NOTE:
If the rig shifts during coring, stop the mo-
tor, reposition the rig and resume coring.
9. Monitor the water flow (see "Diamond Coring").
Generally, water should flow at a rate of approxi
-
mately one to two gallons per minute. If the water
flow is too heavy, the two holes in the water swivel
housing will leak. If that happens, reduce water
flow. Water flow is adequate when the water and
cuttings are flushed in a circular pattern about 1/2"
around the bit. Keep the work area dry.
10.When the cut is complete, keep the drill motor ON
and rotate the handle clockwise to remove the
bit. The bit may become stuck in the hole if you
turn the motor OFF before the bit is completely
removed. Once the bit is removed from the work
surface, turn the motor OFF. Tighten the cradle
lock handle. Unplug the meter box from the power
supply before removing the vacuum pump to
prevent accidental starting of the motor when the
vacuum pump is released.
If you are using a vacuum pump, unplug it and open
the vacuum release valve to release the vacuum.
Retrieving Cores and Deep Coring
When coring holes that are longer than the core bit,
follow the steps below.
1. Begin coring the hole as usual. When you have cored
to the length of the bit, stop the Dymodrill motor.
2. Remove the core by driving a chisel or slender
wedge into the cut between the core and the work
surface. You may also use a special core tongs,
bent wire or anchor bolts to remove the core.
3. After removing the core, reinsert the bit or use a
bit extension and continue coring (see "Acces-
sories"). Removing cores with diameters greater
than twice their length can be difficult. One method
to remove such cores is to first break the core
into smaller pieces and then remove the pieces.
Electric hammers and chisels are ideal for break-
ing cores.
