Trouble Shooting Diamond Core Bits - US Granite Standards

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Wednesday, March 10 2010 @ 04:56 PM EST

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.

Last Updated Thursday, September 17 2009 @ 06:46 AM EDT|176 Hits

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