There are more variable in core drilling than in any other type of cutting. Understanding these factors and how they work together will make you more efficient and cost effective.

If the speed is too high the bit will polish. If the speed is too low the job will take too long.

SPEED: RPMs are referenced to the core drill motor shaft. When you attach a core bit to your motor the size of the bit will determine the surface speed of the diamond segment. The larger the bit size the faster the diamond segment will be moving in relation to the surface of the material. This is why the recommended RPMs of core bits are reduced as core bit sizes increase.

Recommended speeds are average approximations from manufacturers. Bond Specs should factor into your purchase consideration when deciding which bit will perform best with your core drill motor.

Necessary to maintain the proper cutting speed. Efficient cutting means keeping the bit at the right speed.

Not too little and not too much.

Water: The right amount removes slurry and keeps the cut clean. Watch the color of the water, it should be the color of creamed coffee for best results.

You won't "know" until you're done cutting, but understanding the properties of the aggregates that are in your region can help increase your chance of using the best bond for your job.

A good driller will be able to tell if the cut isn't behaving as expected.

Slows the cutting process.

The diamond segments for concrete are designed to hold up against the steel in rebar. However, on rare occassions when drilling you can "hit" rebar head on. In these instances you are not engaging the concrete and your diamond segments can glaze over drastically cutting your drilling speed. Because you can't always avoid hitting rebar head on, you should know how to compensate.

One way is to remove the bit from the cut and re-open the diamond segment. This can be done by a quick cut into soft abrasive material like a cinder block.

Too hard and it takes too long, too soft and it costs too much.

Diamond segments are made up of two major components. The diamonds and the bonding material that keeps the diamonds in place.

When deciding on which product to use a good rule of thumb is that as the Core Bit price goes down, so does the quality and quantity of the diamonds and that can effect your cutting speed and costs. Cheaper bits don't always equal cheaper cuts.

The bond controls the speed at which diamonds are exposed to the cut.. Selecting the right bit within a price range will help control your costs. A soft bond is used to continually expose diamonds when cutting hard materials. A harder bond is used to hold the diamonds to the segment when cutting soft and abrasive materials. The common way to remember is that you use a soft bond to cut hard materials (soft on hard) and a hard bond to cut soft materials (hard on soft). Using a hard bond on hard materials causes the segment to glaze and cutting will be very slow. Using a soft bond on soft material causes the diamonds to be released too fast befor they have been used effectively resulting in very high cost.

A straight cut extends the life of your bit.

When cutting with a core rig, the rig MUST be properly anchored. Use of anchor bolts, vacuum, or a ceiling jack are all acceptable.

STANDING ON THE RIG IS DANGEROUS AND NOT ACCEPTABLE.

A poorly maintained core rig or motor will increase your costs.

Poorly maintained shims, bearings, and hold down devices will increase your costs and may result in damaged core bits and other equipment.