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.

Core Drilling Guide Part 2: Understanding Basic Drilling Components and Requirements

To understand basic core drilling components and requirements, you must familiarize yourself with various drilling tools. This part of the guide aims to throw light on this aspect of drilling.

Different Types of Drilling Equipment

For successful core drilling, you need equipment that ensures the best results from your endeavours.

Other factors such as coolants, RPMs, and feeds with the diamond bit or drill should also be taken into account. Remember even the best quality diamond drills will fail when paired with the wrong equipment.

Use them with equipment such as

  • Drill Press
  • Milling/CNC Machine
  • Hand Held or Angle Grinder
  • Air High Speed Spindle
  • Hand Held or Cordless Grinder

So who uses drill equipment such as CNC Machine or Drill Press? These are industrial manufacturing units, R&D departments, homeowners, hobby enthusiasts, and contractors. They use drills of the handheld variety, angle grinders, drill presses, and drilling rigs.

Various Applications

How often will you be using your diamond bits or drills? What specific tasks do you need them for? Your answers will help you determine your drill requirements.
These bits and drills have a wide application:

a) Production & Industries

They are part of standard equipment in many production and manufacturing operations. These include aerospace composite application, ceramic parts technical or advanced machining, countertop stone fabrication, and lens optical machining.

Machinists and engineers demand a high level of consistency, accuracy, and yield from their drill bits. For heavy-duty applications involving thousands of drillings per day, sintered metal bond drills are ideal.

b) Craft & Hobby

When it comes to art and craft projects, diamond bits or drills come in handy for working with glass, river rocks, beads, jewelry and lapidary.

One thing these applications have in common is that you can use these drilling gadgets occasionally for specific requirements and then keep them stored away.

For, something less than 100 holes, use nickel bonded electroplated drill. These are ideal for beginners since they are more forgiving to mistakes and errors.

Save time money and frustration, by choosing the right drill for your projects.

c) Research and Development

Whether it’s about drilling holes or obtaining core samples, nothing tests the limits of diamond bits or drills more than research and development.

The field is diverse and so are the requirements of researchers.

Research applications involve numerous fields such as advanced materials, material science, geology, optics, metallography, and technical/advanced ceramics.

Also, breakthroughs and new fields such as Nano, Biotechnology, and MEMS use such drilling equipment for various applications.

Typical application scenarios include

  • Commercial Laboratories
  • Large organization R&D
  • Government Laboratories
  • Military Research
  • Universities
  • Science & Space

As the core drilling requirements increase, diamond bits and drills are available at increasing levels of quality, ensuring the best results for various projects.

Core Drilling Guide Part 1: Introduction to Core Drilling

Are you ready to obtain the best drilling results for your project? If so, you need to determine what kinds of diamond bits or drills are perfect for the job. This is important since knowing the right tools to use will save you both time and money.

To which category do you belong? Are you a novice, an experienced engineer, hobby enthusiast, researcher, or a contractor? Knowing this will help narrow down your choice to the types of diamond bits that are most appropriate for completing your project.

To ensure that everything goes smoothly, take heed of these three prerequisites to core drilling success:

  • Proper detailing
  • Suitable preparation
  • Following basic techniques

Type of Material

What kind of material are you working with in your core-drilling project? What are its features or characteristics? This will help in determining the tools and techniques you’ll need to obtain the desired outcome.

The kind of material you are planning to drill is an important consideration in your choice of drills:

a) Hardness of Material

For ultra-hard Alumina, Sapphire, natural/precious stones, materials with high metal content and advanced ceramic; metal bonded sintered diamond drills are the best.

For less expensive or softer materials such as tile, soft stones, glass, and composites, nickel bonded electroplated diamond drills work the best.

The basic rule for core drilling is that you will require soft bonds for hard materials, for free and fast drilling. Similarly, abrasive or softer materials require hard bonds for long-lasting performance.

b) Cost of Material

What kind of material are you going to drill? Determine how expensive it is. For expensive or precious material, the cost of the bit or drill matters little.

The use of a diamond thin wall core drill will help minimize deformation and loss of material. Having an estimate related to per-hole quality and target cost surely helps.

c) Density & Geometry of Material

Each type of material has a specific composition, density, and hardness. A method or technique that works for one, may not work for the other.

If you are looking for optimal, consider custom diamond drills that suit perfectly the type of material you’re planning to drill.

Material properties such as brittleness, size, shape, hardness, and diameter, will help in your choice of bits, clamping methods, feeds, speeds, and drilling equipment.

d) Thickness of Material

The thickness of the material you’re drilling determines how much pressure and coolant to use.

Multiple direction coolant works the best with through the drill, coolant submerged drill, and from the sides. This ensures enough lubrication and coolant will reach the drilling zone.

Running the coolant at high pressure through the diamond bit/drill centre using a swivel water adapter is ideal for drilling a material thicker than 1 inch or 25.4 mm. With, long-depth drilling you will require a stepwise mechanism using multiple bits or drills.