Core Drilling Guide Part 3: Output Quality versus Technical Requirements

What output quality do you want from your drilling project? Your answer to this question will help determine what kind of drill bit to use.

Here are the two most common user requirements:

a) Material hole

– Drilling tasks in most cases involve creating a round and even hole. For such applications, you should use either a hollow or a solid drill. Hollow drills can be quite fast and efficient. The primary application for solid drills is in drilling primary holes in the range of .001” to 3/8”. On the other hand, hollow core drills are for drilling larger holes.

b) Obtaining material plug– Obtaining a material core is often the main reason for using diamond core drills. For this purpose, hollow drills offer the best results. The inner diameter of the core drill plays a critical role in such cases. Manufacturers take special care in developing drills with differing tolerances and specifications.

Aside from these two major requirements, there are other less common ones:

Finish or chipping requirements– The grit or mesh size of the diamond drill determines the finish quality of the surface, chipping level, microstructure deformation or damage of material, and smoothness.

In situations where chipping and surface finish are a critical factor, the perfect tool would be a metal bond, sintered diamond drill with very fine grit.

For getting the highest surface finish quality, you should use electroplated multi-layered core drills with a swivel water adapter running a high-pressure coolant. Water-soluble synthetic coolants offer the best surface finish results.

Cost of material– When the material drilled is expensive, valuable or precious, the associated drilling costs take a backseat.

Use thin walled drills to minimize deformation and loss of material. However, when it comes to cost of materials it is necessary to have a prior estimate of the target cost versus the quality of the resulting job.

Tolerances– To work with materials with specific tolerances you will need custom drills that are designed for very specific tasks.

Specification of tolerances may depend upon concentricity, run out, OD, and ID of diamond drills.

Use of coolant

Did you know that different drills have different coolant requirements? If you’re using a core diamond drill, use a coolant for the best results.

Regular drilling projects can use tap water, mineral oils, or a water-soluble synthetic coolant.
Using a drill dry will most certainly result in shorter drill life and the deformation of the material being drilled.

Nickel bonded electroplated drills are often used for dry drilling even if this is not the recommended method.

Five Essential Tips For Core Drilling

Core drilling is the process by which core is extracted from specified places of the concrete slab or wall for doing strength tests.

It is recommended to hire professional concrete drilling or sawing company for core drilling or concrete cutting tasks. Hence, if you wish to give a try on your own, here are some tips to help you to become the best choices available and ensure the success of your core-drilling project.

Choose the Right Drill Machine

There are different kinds of drill machines available for use on concrete. You may choose to either rent them or purchase them for good. Core handheld drills allow the creation of holes, which are up to a diameter of 3 inches. However, for successful spring testing of concrete you need to drill a hole, which is at least 3.7 inches in diameter. For this reason, you will need to use rig-mounted or drill stand units. For those who are considering the purchase of such units it is necessary to go for multifunction purposes. This way you can ensure the best value for the money spent. You can use them for dowel-hole drilling or electric/plumbing holes.

Find Suitable Stand Attachment

Based on where you need to drill holes specific stands are required. For example, for doing it on slabs having flat surfaces just use vacuum stands that use suction power to keep it attached to the floor. In such cases, you do not need to drill anchor holes. For core drilling in the walls, securing the stand on it is necessary. Presence of safety chains with stands prevent accidental slipping.

Consider Your Power Options

For powering the core drill one can go for one of the three available options. This includes electric, hydraulic, and air-powered sources. The work environment along with the availability of power on the jobsite determines the type of source ideal for your requirements. Units available in the market allow appropriate speed choices related to concrete hardness and hole-size.

Consider the Drill Depth

Regular core drilling requirements can be dealt with successfully using simple 1-foot long bits. For drilling requirements higher than this, utilisation of barrel bits will do quite well. The barrel bits are bit extensions allowing deeper core drilling compared to the size of existing cutting bits. You can move to increased depths based on requirements, using such drilling extensions. Consider the type of extension you may require for getting the best results in specific scenarios.

Choosing a Diamond Bit

For choosing the appropriate core diamond bit, users need to consider the aggregate hardness and psi of the concrete surface to be used for drilling purposes. In to get the best effects the core diamond bit needs to be in complete proportion to the drilling material or surface. The basic rule of thumb is that construction workers should use a soft diamond bond for core drilling on hard surfaces or materials. Similarly, they should use a hard diamond bond for core drilling on soft surfaces or materials. There is no single solution available that affects all and one needs to consider their choices based on the current situation and drilling require for ensuring project success.