Trouble Shooting Diamond Core Bits
|
| Glazing (bit stops drilling or is very slow) |
| Cause |
Too much feed pressure. |
| Remedy |
Open bit with abrasive material (sand pot, concrete block, chop saw blade). Reduce feed pressure. Use of an ammeter will help to control speed and pressure.
|
|
| Cause |
Aggregate is too hard. |
| Remedy |
Use a softer bond. |
|
|
| Bent Segments |
| Cause |
Too much feed pressure and not enough water. |
| Remedy |
Repair the bit if possible. Ease up on feed pressure and increase water flow. |
|
| Cause |
Aggregate is too hard. |
| Remedy |
Use a softer bond. |
|
|
| Lost Segments |
| Cause |
Steel reinforcing rod. |
| Remedy |
Ease up on feed pressure (watch ammeter). Use a higher quality bit and increase the water flow. |
|
| Cause |
Not enough water to properly cool the bit. |
| Remedy |
Increase water flow. |
|
| Cause |
Drill rig is not properly anchored. |
| Remedy |
There are three ways of anchoring a rig - standing on the rig is not one of them! |
|
|
| Core Hangs Up |
| Cause |
Not enough water to remove slurry. |
| Remedy |
Remove bit and drive core out with a spike through the hub. Increase water flow. |
|
| Cause |
Core barrel is dented because of hammering on it to remove hung up cores. |
| Remedy |
Repair the barrel and increase water flow. |
|
|
| To Remove a Stuck Bit |
STEP 1
Disconnect the core rig from the bit. |
STEP 2
Thread a piece of threaded rod the same diameter as the bit (5/8-11 or 1-1/4-7) through the hub until it hits the concrete. Then place two hex nuts on the rod and lock them against one another so that they in turn lock themselves to the rod. |
STEP 3
Turn the nuts with a wrench which will turn the rod which will in turn push against the concrete core, pulling the bit from the hole without damaging it. |
