Pg15, Drilling a hole, Continuing a partial-hole – Diamond Products UDM User Manual

Page 18: Stuck cores, Removing a stuck core, Stuck bits

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Drilling a Hole
Reminder: Always refer to the Drill Mode section in

Operating the U to set the cylinder pressure and drill

motor pressure prior to drilling.

1. Position the machine and core bit.

2. Move the function switch to Drill.

3. Lower the front mast and rear legs. All tires

should just clear the ground and the front and

rear tire height should match up so the machine

is level.

4. Turn on the Vacuum switch and close the

vacuum valve. Check the vacuum gauge for

pressure; stop to determine the problem when

suction fails. Skip this step if the vacuum cannot

be used when drilling.

5. If the machine is equipped with a 2-speed drill

motor, set the motor to High for bits up to 10”

and Lo for bits larger than 10”.

6. Adjust the Drill Rpm cartridge based on the bit

size. Refer to the core drilling speeds chart on

the machine for the recommended core bit

speeds when drilling. DO NOT exceed the

maximum recommended drilling speed.

7. Turn on the Water switch.

8. Turn on the water valve and adjust the water

flow valve to increase or decrease the water

flow. Note: Always have a proper water

pressure and flow when drilling for maximum

core bit efficiency. DO NOT continue drilling

when a problem arises with the water system.

9. Push the Drill Down button and SLOWLY lower

the bit to start the hole. Once ground contact is

made continue drilling to the desired depth, or

release the Drill Down button and turn the Auto

Drill switch to On/Drill (the bit will lower until the

cylinder fully extends or until Auto Drill is turned

off) to drill to the desired depth. DO NOT use

Auto Drill until after the bit has contacted the

surface to prevent serious injuries or damage to

the machine.

10. Release the Drill Down button or turn off the

Auto Drill switch.

11. Press the Drill Up button to raise the bit out of the

hole. Note: Pressing the Turbo and Drill Up

buttons together will raise the bit quickly.

12. Turn off the Drill Rpm cartridge.

13. Decrease the water flow and turn off the water

valve and Water switch.

14. If used, turn off the Vacuum switch and open

the vacuum valve to release suction.

15. Lower all tires to the ground. Note: Make sure

the mast and rear legs are fully lifted for

maximum ground clearance.

16. Move the function switch to Start/Drive.

Continuing a Partial-Hole
1. Inspect the drill hole and remove, if possible,

items that may cause the bit to stick (lost core

bit segments, broken concrete).

2. Align the bit with the previous hole and slowly

lower the bit back into the hole. DO NOT drill

unless the core bit is aligned with the hole.

3. Finish drilling the hole following the directions

directly above.

Stuck Cores

Removing a Stuck Core
4. Remove the core bit from the machine.

5. Move the bit away from the work area.

6. Lay the bit on the ground. DO NOT hammer on

the core bit to avoid denting the tube, which

can result in additional problems and increased

hang-ups.

7. Option 1:

a) Place a metal spike through the hub and

drive the core out of the bit.

b) Inspect the bit for damages and clean or

replace as necessary.

8. Option 2:

a) Thread a piece of threaded rod (1-1/4-7)

through the hub until it contacts the

concrete.

b) Place two hex nuts on the rod end and lock

them against each other.

c) Holding the bit in place, grasp both nuts

using a wrench and turn to push the rod

against the concrete, which will drive the

core out of the bit.

d) Inspect the bit for damages and clean or

replace as necessary.

DO NOT hammer or pry on the bit! This will dent the
tube, which can result in additional problems and
increase hang-ups.

Stuck Bits

Stuck core bits happen most frequently in the

following circumstances:

An insufficient water supply allows slurry to

accumulate, causing the drill to seize.

Pushing the drill down too hard can cause

the machine’s frame to shift slightly (more

susceptible when not using the vacuum).

Drilling completely through a slab may

cause segments to catch at the bottom

edge of the hole when raising the bit.

Partially cutting through a piece of rebar

with just the outer edge of the bit (mooning)

can deflect the bit, causing it to jam. Slowly
cutting through rebar or hard spots may help.

15

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