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Selecting the Right Diamond Drill / Bit for your application

Selecting the right Diamond Drills/Bits for your application is key to obtaining desired diamond drilling results. Using the Right Diamond Drill will help you Save Time & Money. As well as avoid an unnecessary trial & error process. The article below was designed for diamond drill/bit users of all skill and experience levels. Ranging from beginner (novice) to experienced manufacturing engineer, researcher, contractor or hobby enthusiast. The following are some factors to consider when selecting the right diamond drill for your application.  

 How to select the right Diamond Drills, Equipment, and Accessories (366kb) 
How to properly use Diamond Drills (543kb) 
How to properly use Diamond Tools (171kb) 



Today's growing variety and ever changing materials, Manufacturers, R & D facilities, hobbyists and everyone else involved in diamond drilling encounter wide variety of applications and challenges. The ever increasing variety of advanced, new generation, ultra hard, composite, micro, and exotic materials transform the way we look at diamond drilling. And set many age old diamond drills/bits and drilling methods obsolete. New materials require different technology and methods. 

And although, today's market place offers the Manufacturing Engineer, R & D Scientist, Hobby Enthusiast, Contractor and Home Owner hundreds of choices of diamond drills/bits, accessories, and equipment. It offers little advice on how the user can implement these tools to accomplish their specific objectives. Many users still spend days and even weeks, trying different diamond drills/bits, and experimenting with different types of drilling equipment. An expensive and time consuming trial and error process, which can be avoided with proper understanding of your material and objectives you need to accomplish. Proper preparation, attention to detail, and following basic diamond drilling technique can make the difference in the success of your diamond drilling operation. 

Material to Be Drilled    

a.)    Hardness of MaterialMaterials you are planning to drill will have a large impact in the types of diamond drills,  equipment, and accessories you will be able to use. If you are drilling ultra hard materials such as sapphire, alumina, other types of advanced ceramics, high metallic content materials, precious and natural stone. It is generally recommended that you use a sintered (metal bonded) diamond drill. However, if you are drilling softer and less expensive materials such as glass, composites, soft stone and tile, an electroplated (nickel bonded) diamond drill may be a better and more cost effective solution. As a rule of thumb harder materials require softer bond, to drill faster and freer. While softer and abrasive materials require a harder bond, to last longer. Material Hardness is defined as the materials capability to resist deformation. All materials are classified by their scale of hardness. Material hardness is measured by many different hardness scales such as Mohs, Vickers, Knoop and other scales of hardness. Further information on determining and understanding hardness of your material is available in this article below.

b.)    How expensive is your material - Material cost will play an important role in selection of the right diamond drill/bit for your application. if the material you are planning to drill is precious, valuable, or expensive. Diamond drill/bit cost will play a minor role in your drilling operation. It is suggested that you obtain a thin wall diamond core drill to minimize material loss and deformation. It’s always a good idea to have some type of an estimate of target cost and quality per hole.


c.)    Material Thickness (maximum drilling depth) – The thicker the material you are planning to drill, the greater amount of coolant and pressure is required. Applications requiring you to drill over 1" (25.4mm) should be tread in a different way. We recommend running  coolants from multiple directions. Through drill center, from side of drill, as well as drilling submerged in coolant. This will insure maximum amount of coolant and lubrication reaching your drilling zone. Running high pressure of coolant through center of your diamond drill/bit by using a water swivel adapter is highly recommended for drilling material over 1" (25.4mm) Thick. Longer Drilling depths may require drilling in several steps and using more than one diamond core drill / diamond drill bit.


d.)  Material Geometry & DensityEach material has different density, hardness, composition. For this reason a diamond drills/bits and techniques that may work on one material, may not work on another material. To obtain optimum drilling results, each diamond drill should be ideally made to factor in the unique differences and properties of each material. Shape, Size, Diameter, Hardness, and Brittleness of your material will affect not only your diamond drill/bit selection, but your choice clamping methods (holding your material in place), drilling equipment, speeds & feeds you can use.



Equipment to be used

The equipment you will be using and its physical condition, will dictate the speeds (RPM’s), feeds, and coolants you can use along with your diamond drills/bits. Hence, somewhat limiting your diamond drill selection. No matter what diamond drill you use or how well its made, it will not provide the performance you are looking for, if you don’t use the right drilling equipment for your application. Diamond drills are usually used on the following equipment: 

a.)    Drill Press

b.)    Angle Grinder/Hand Held Grinder

c.)    Cordless Drill / Hand Held Drill

d.)    CNC / Milling Machine

e.)    High Speed Air Spindle

e.)    Many Other Types of Equipment 

Drill presses, milling machines, or CNC machines are used in most industrial manufacturing applications. R & D facilities also tend to utilize the same equipment. Hobby Enthusiasts, Contractors, and Home Owners most often use hand held Drills, followed by drill presses, drilling rigs, and angle grinders. Proper drilling equipment for your diamond drilling application is discussed in further detail in this article below.

Number of Holes to be Drilled

Your diamond drill requirements will greatly vary with your application & frequency of use and diamond drill/bit intended application. Diamond Drills, Diamond Core Drills, Diamond Drill Bits, Diamond Bits (usually mean same thing) are generally used for:  

a.)    Industry / Production - Diamond Drills/Bits are used everyday in thousands industries & operations to manufacture products that play an important role in our everyday lives. Ranging from advanced/technical ceramic parts machining, composite aerospace applications, optical lenses machining, stone countertop fabrication and much more. Diamond Drill & technical requirements are diverse as the manufacturing operations that use them. Typically manufacturing engineers & machinists demand a high level of consistency, accuracy, yield (output per cost) from their diamond drills/bits. What is common about these applications is the Diamond Drill/Bit will be used every day or several times a day, drilling several thousand holes/cores or until the drill is warn out and replaced. Metal Bond (Sintered) diamond drills are usually recommended for this type of heavy duty use. However, if you have a very fine or specific finish requirement and do not polish material after drilling. HYBRID Bond diamond drill or even Multi-Layered Electroplated Diamond Core Drills used with water swivel adapter to run high pressure of coolant through center of your diamond drill/bit may be the best solution for your application. No matter what stage your manufacturing operation, UKAM Industrial Superhard Tools has the Experience & Solutions to help you resolve even the most complex manufacturing challenges. Discover why thousands of manufacturing around the world turn to UKAM Industrial Superhard Tools to optimize their diamond drilling & machining operation to ultimate level of efficiency.  


b.)    Research & Development - Diamond Drill requirements in Research are diverse as fields and researchers that used them. Whether is drilling a hole or obtaining core sample. Most researchers & application engineers are primarily concerned about preserving material true micro structure and introducing least amount of damage & deformation possible to material being worked on. Research Applications range from materials sciences, advanced materials, advanced/technical ceramics, optics, metallography, geology, composites to new and breakthrough fields such as MEMS, Biotechnology and Nano Technology. Typical Research diamond drill/bit users include Universities, Government or Commercial Laboratories, Military Research Facilities, Space & Science Organizations, as well as R & D departments of large organizations. UKAM Industrial Superhard Tools understands the challenges faced by faced by R & D Organizations and has developed diamond drills/bits, accessories, and TOTAL SOLUTIONS to address most common R & D applications. We are constantly engaged in R & D and process development ourselves to keep up with increasing demands of the complex / advanced material world / community.


c.)    Hobby / Craft – Diamond Drills/Diamond Drill Bits are used for thousands of diverse type of art & craft applications. Materials frequently range from river rocks, all types of glass, jewelry, beads, lapidary (semi precious & precious stones). What is common about many of these applications is that the diamond drill will be used occasionally for a specific job and than stored for later use. If you are planning to make less than a 100 holes, we recommend you use an electroplated (nickel bonded) diamond drill. Electroplated diamond drills are recommended for beginning (novice) users, because they are usually more forgiving to operator error & mistakes. However, if you are planning to use the drill a number of times through the year. Sintered (metal bonded) diamond drill is a better overall solution and investment. Whether you are just starting out or are an experienced/accomplished crafts person, UKAM Industrial Superhard Tools has the solution to optimize your diamond drilling operation and help you reach the next level. Save money, time, and frustration. By using the right diamond drill/bit for your application the first time. Discover why the leading artisans commissioned by well known organizations such as Faberge, Courtie, Antique Restoration Houses, well known glass & stained glass artists, and jewelry manufacturers use & prefer diamond drills/bits manufactured by UKAM Industrial Superhard Tools.


User Goals / Objectives

a.)  Drill Hole in Material - most drilling application involve drilling holes in variety of materials. In this case a hole is the end product. And obtaining an even, round hole is the desired result. The users focus should be on (OD) Outside Diameter of the drill. Either a hallow Diamond Core Drill or Diamond Solid Drill (without hole) can be used for this application. Faster drilling speeds and more efficient drilling results will be obtained with a so called Hallow Diamond Core Drill. Diamond Sold Drills are primarily used for drilling smaller size holes from .001" to 3/8". Hollow Diamond Core Drills are used for drilling larger size holes.

b.)  Obtain Core (material plug) - for some diamond drill users, obtaining the material core (center plug) that becomes stuck inside the core drill is the desired result. In this case the material core (plug) is the end product, not the hole itself. A core can only be obtained using so call "hallow diamond core drill". The diamond drills (ID) Inside Diameter becomes a critical dimension (parameter). We often manufacture diamond core drills, specifically to fit each individual customers requirements and tolerances. Please, specify that you need to obtain the Core when ordering diamond drills. Inside Diameters (ID) for most of our standard stock drills are listed in our web site. Ejecting the center core from center of diamond core drill becomes an important factor. Core can be manually removed from core drill through center of drill or slots provided on body of diamond drill. The most efficient way of removing core from center of drill, is using high pressure of coolant from water swivel adapter. Just increase pressure of coolant, every time core becomes stuck inside your drill. This is the fastest, easiest, and most efficient method for removing material center core.

Technical Requirements/Specifications

d.)    Chipping/Finish Requirements – Diamond Mesh Size (grit size) of your diamond core drill/drill bit will play a major role in determining the surface finish quality, smoothness, level of chipping, and material microstructure damage/deformation you will obtain. if you have an application where surface finish and chipping is a critical factor, a sintered (metal bond) diamond drill with a very fine diamond grit may be the best solution. Using Multi-Layered Electroplated Diamond Core Drills in combination with water swivel adapter to run high pressure of coolant through center of your diamond drill/bit. And synthetic water soluble coolant will help you obtain the best surface finish quality possible. More detailed explanation of diamond mesh size in correlation to surface finish quality is presented in this article below.


e.)  Tolerances – if you are using diamond drills to drill holes in a product that requires on specific tolerances, you will need a custom diamond drill specifically designed for your application. Tolerance may be specified on OD, ID, run out and concentricity of the diamond drill.


f.)   Material Cost – if the material you are drilling drill precious, valuable, or expensive. The diamond drill cost will play a minor role in your drilling operation. It is suggested that you obtain a thin wall diamond core drill to minimize material loss and deformation. It’s always a good idea to have some type of an estimate of target cost and quality per hole.


Coolant to be used

Your capability to use coolant while drill, will seriously effect your diamond drill selection. Most diamond core drills must be used with coolant. Typical coolants used with diamond drills/bits include regular city water, synthetic water soluble coolant, & mineral oil. Shorter drill life, material and drill deformation will result when using drills dry. Electroplated (nickel bonded) diamond core drills may be used dry (without water) depending on the application (material being drilled). UKAM Industrial Superhard Tools does have the capability to manufactured diamond drills to be used without coolant. However, using diamond drills dry is not recommended on most applications. When chance prevails, use all diamond drills with coolant. If use of coolant with your diamond drill/bit is not possible for fear of contamination or any other reasons, consider using compressed air as form of coolant. Although it will not substitute coolants described above, it will be better than drilling dry.

Diamond Drill Variables


Bond Hardness – Ability of the bond matrix to hold diamonds. As the hardness of the bond is increased, its diamond retention capabilities increase as well. However the trade off is slower drilling speed. Life of the diamond drill is usually increased with hardness of its bond matrix. Bonds are designated on their scale of hardness from Soft, Medium, and Hard. There are dozens of variations and classification schemes based on bond degree of hardness or softness. Using diamond drills with optimum bond hardness for your application is important to successful drilling operation. Bond matrix that is too soft for the material being drilled will release diamond particles faster than needed, resulting in faster wear and shorter diamond drill life. On other hand bond matrix that is too hard will result in much slower drilling speeds and require constant dressing to expose the next diamond layer. As rule of thumb, harder materials such as sapphire and alumina (Al203) generally require a softer bond. Whereas softer and more brittle materials require a harder bond.





Diamond Grit Size (Mesh Size) – grit size (mesh size) is generally selected depending on the speed you wish to operate the drill and surface finish of your material. The size of the diamond crystals, commonly referred to as mesh size, determines the number of diamond cutting points exposed on the surface of a diamond drill. Diamond Mesh/Grit Size is similar to various grit sizes found on sand paper, which usually comes in coarse, medium, find, & super fine grits. According to U.S. Standards, mesh designates the approximate number of sieve meshes per inch. High Mesh Sizes mean fine grits, and low numbers indicate coarse grits. Diamond Mesh Size plays a major role in determining the surface finish quality, smoothness, level of chipping, and material microstructure damage/deformation you will obtain

Finer mesh size diamonds such as 220 and 320 grit are much smaller in size than coarser diamond particles. And will give you a very smooth surface finish, with minimal amount of chipping on edges. These mesh sizes are usually used for drilling advanced and optical materials such as:  LiNbO3, YVO4, GaAs, and optical materials.

 Courser diamond particles such as  80 and 100 grit are much larger in diameter and are frequently used fast drilling / material removal on more harder materials such as granite, sapphire, stone, silicon carbide, zirconia, Al2O3, stainless steels, and other advanced ceramics and materials with high metallic content. Which usually do not require a very fine surface finish.  


The diamond mesh size in a cutting tool also directly relates to the number of crystals per carat and the free cutting capability of the diamond tool. The smaller the mesh size, the larger the diamond crystals, while larger mesh size means smaller diamond. A 30/40 Mesh blocky diamond has about 660 crystals per carat, while a 40/50 Mesh diamond will have 1,700 crystals per carat. Specifying the proper mesh size is the job of the diamond drill manufacturer. Producing the right number of cutting points can maximize the life of the tool and minimize the machine power requirements. As an example, a diamond tool manufacturer may choose to use a finer mesh size to increase the number of cutting crystals on a low concentration tool, which improves tool life and power requirements.

Diamond Mesh size does have considerable effect on drilling speed. Coarse Diamonds are larger than finer diamonds and will remove more material than finer diamond particles. This means that coarse diamond drills are more aggressive for material removal than the finer diamond drills and will drill faster. However, the tradeoff is increase in material micro structure damage. If you are drilling fragile, more delicate materials then finer mesh size diamond drills are recommended. Diamond mesh size (grit size) should provide maximum removal rate at minimal acceptable finish. Often the desired finish (hole/core quality) cannot be achieved in a single step/operation. Lapping or polishing may be necessary to produce desired surface finish, as a secondary step in your diamond drilling operation / process.

Understanding Diamond Drill/Bit Mesh/Grit Size & Surface Finish Quality

When converting from conventional abrasives such aluminum oxide or silicon or sand paper grit size to industrial diamond mesh size, double the conventional abrasive grit size to find the equivalent industrial or natural diamond mesh (grit size) for your diamond drills/bits. For example: a 60 grit Aluminum Oxide would equal 120 grit in diamond.

Diamond Definition Diamond Mesh/Grit Size

Diamond Micron Size

Recommended Application

Approximate RMS
Saw Grit 40/60


Sawing 125-200
Super Course 60/80


Roughing (Heavy Stock Removal) 125-150
Large Course 80/100


Medium Roughing (General Drilling) 90-125
Course 100/120


Semi Roughing  (Semifinish Drilling) 64-90
Medium 140/170


Rough Finishing (Finish Drilling) 32-48
Fine 200/230 68 Finishing 20-24
Extra Fine 270/325 49 Fine finishing 14-16
Super Fine 325/400 47 Extra finishing 14-15
45 Microns* 400/500 45 Super finishing 13-14
30 Microns* 500/600 30 Polishing 12
15 Microns* 800/1200 15 Polishing 12
9 Microns* 8/10 6/12 1,800 9 Polishing  
6 Microns* 4/8 3,000 6 Fine polishing  
3 Microns* 8,000 3 Extra polishing  

Diamond Concentration - The proportion, and distribution of diamond abrasive particles, also known as concentration. Has an effect on overall drilling performance and price of your diamond drill. Diamond concentration, commonly referred to as CON, is a measure of the amount of diamond contained in a diamond section of drill based upon volume. Diamond Concentration is usually defined as: Concentration 100 = 4.4 ct per cm layer volume (mesh size + bond). Based on this definition a concentration of 100 means that the diamond proportion is 25% by volume of diamond layer, assuming at diamond density is 3.52 g/cm3 and 1 ct = 0.2g. Nominal diamond concentration in precision diamond drills range from 0.5 ct/cm3 to 6 ct/cm3. This means diamond concentrations are available from 8 to 135). Selecting the Right Diamond Concentration can be critical in optimizing your Diamond Drilling Operation. Selecting Optimum Diamond Concentration for your application will depend on a large number of factors, such as:

  • Material Being Drilled

  • Diamond Drill Bond Type and Hardness

  • Diamond Mesh Size

  • Drilling Speeds

  • Coolants being used

Diamond Concentration will play a major role in determining the life and drilling speed of your Diamond Drill. Higher diamond concentration is recommended and usually used for cutting softer and more abrasive types of materials. However, the trade off is significantly slower drilling speed. Low diamond concentration is recommended and widely used for drilling ultra hard and brittle materials. Optimum performance can be achieved when the diamond tool manufacturer utilizes their experience and analytical capabilities to balance diamond concentration and other factors to achieve optimum performance for the diamond drill/bit user. UKAM Industrial Superhard Tools has the experience & applications laboratory to help you select all the right variables for your unique application.

Wall Thickness – the thinner the wall thickness of your diamond drill/bit, faster the speed (RPM) your drill may run, less chipping and heat your drill generates, and smoother and higher quality of the finish. Thin wall diamond core drills provide the following advantages:

  • less loss of material

  • minimum material deformation

  • less heat generation

  • faster drilling speed

  • less chipping

  • better finish quality

The trade off is shorter diamond drill life. Thin wall diamond core drills will wear much faster thicker wall diamond drills. UKAM Industrial Superhard Tools has the capability to manufacture diamond core drills with wall thickness as ULTRA THIN as .003" (76 microns) to as thick as .236" (6mm) & as thick as you want  


Most often used collets are 5/8-11", 5/8-18, 1-14, 3/4-16, 7/8-14, 1-1/4-7", BRANSON (Ultrasonic) and Others. Standard shank sizes are usually 1/4", 3/8", and 1/2" diameter

UKAM Industrial Superhard Tools manufactures & stocks Diamond Drills/Bits to customer desired specifications, outside & inside diameters, drilling depths, bond types, diamond grit sizes, mountings, & tolerances. Below is a diagram (technical drawing) that will help you better understand different diamond drill/bit specifications that can be altered based on your requirements.

Diamond Core Drill/Bit Mounting Methods: Diamond Drills/Bits must be either mounted on a collet or made with straight shank. Diamond Drills mounted on a collet can be used with water swivel adapter to run high pressure of coolant through center of drill. Diamond drills with straight shank are meant to be placed in drilling machine chuck and cannot be used with water swivel adapter. We recommend using diamond drills/bits that are mounted on a collet. You can always purchase a shank adapter that will thread into the collet, that will convert your diamond drill into a straight shank mounting. Various industries used different collets (mounting methods). 


TH = Drill Tube Wall Thickness  TH1 = Outside Diameter Diamond Section Relief   TH2 = Inside Diameter Diamond Section Relief


D = Outside Diameter   D1 = Inside Diameter  D3 = Shank Diameter  

D4 = Shank Inside Diameter


H = Total Drill Length  H1 = Diamond Depth (diamond height)  H2 = Drilling Depth (how deep you can drill)  H3 = Shank Length

Offcentric Diamond Drill: Designed with what is commonly called Half Moon shaped ID, allowing the core drill to move material and coolant at the same time as it drills the hole. ID (Inside Diameter) of the Diamond Drills/Bit is made larger (off center). OD (outside diameter) is made smaller to accomplish this purpose.

Non Coring / DISINTEGRATING ID Diamond Drill: Inside diameter of this diamond drill is offset. It is still considered a diamond core drill because it has a slot on side for coolant to pass through center of the diamond drill. This type of diamond drill leaves no core behind (destroys core when drilling), because its  ID (inside diameter) is Offset.

Slotted Diamond Drill Design - Making slots in diamond drill tip will usually make them drill faster and freer in hard materials. Slots help reduce diamond drill heat generation, and better propel coolant through the drilling zone. The width of slot depends on hardness of material. Diamond Drills manufactured for drilling harder materials require more slots than diamond drills made for softer materials. Slots are recommended for thick wall diamond drills, helping increase drilling speed and efficiency.


Find out more...  What you should know before you buy your next diamond drill

For more & help on selecting the right diamond drill for your application. Contact UKAM Industrial Superhard Tools Engineering Department at Phone: (661) 257-2288.

Understanding Material Hardness & its Affect on Diamond Drill/Bit Performance

Material Hardness has several meanings. Most common definition for material hardness refers to its ability to resist deformation. Scientifically hardness is defined by energy density (energy per unit volume) required to create strain in material. While there are many ways, scales, and classification schemes to measure material hardness. In this article we will address the most simple explanation.

Mohs scale of Abrasion Hardness is the most simple and well known material hardness measurement and classification methods. In this scale material hardness is measured by scratch test of rubbing each material against another. All material harnesses are arranged in 10 ranks. Each rank is calibrated by a standard mineral. Below find these minerals in their rank of hardness from softest to hardest.

Mohs Scale of Hardness
1 Gypsum
2 Calcite
3 Fluorite
4 Apatite
5 Orthoclase
6 Quartz
7 Topaz
8 Corundum
10 Diamond

Hierarchy of Material Hardness

Hierarchy Rank Examples of Minerals / Materials
Ultrasoft < 5 graphite, salt, talc, lead, teflon
Soft 5-8 silver, copper, calcite, fluorite
Normal 8-10 magnesia, glass, steel, quartz
Hard 10-12 WC, SiC, Al203, Si3N4, B4C
Superhard > 12 cubic boron nitride, Diamond

Proposed Scale of Hardness for Industrial Materials
Material Formula Mohs Hardness Knoop Hardness Rank Industrial Hardness
Graphite C 1 -  12 3.6 3
Molybdenite MoS2 1 17 4.1 4
Aluminum, annealed Al 2 - 25 4.6  
Table Salt NaCl 2 30 4.9  
Gypsum CaSo4 2 32 5.0 5
Silver Ag 2+ 60 5.9 6
Mild Steel, annealed Fe 2+ 123 6.9  
Calcite CaCO3 3 135 7.1 7
Copper Cu 4 163 7.3  
Indium Antimonide InSB 4+ 220 7.8 8
Magnesia MgO 5- 370 8.5  
Glass Soda lime 6- 530 9.0 9
Tool Steel Fe 6+ 700 9.5  
Quartz SiO2 7 820 9.7  
Chromium Cr 7 935 9.9  
Zirconia ZrO2 8- 1160 10.2 10
Cemented WC WC-Co(8%) 8- 1200 10.2  
Beryllia BeO 8- 1250 10.3  
Silicon Se 8 1400 10.5  
Titanium nitride TiN 9- 1800 10.8  
Corundum Al203 9 2100 11 11
Silicon Nitride Si3N4 9 2100 11  
Tungsten Carbide WC 9+ 2400 11.2  
Titanium Carbide TiC 9+ 2470 11.3  
Silicon Carbide SiC 9+ 2880 11.5  
Boron Carbide B4C 9+ 3000 11.6  
Sintered cBN BN 10- 3200 11.6  
Cubic boron nitride BN 10- 4800 12.2 12
Sintered diamond C 10- 5000 12.3  
Diamond (Type IIa) C 10 9000 13.1 13

Understanding Diamond Drill/Bit Bond Types & their Application

Sintered (Metal Bond) Diamond Drills

Metal bonded diamond core drills have diamonds sintered and multiple layers of diamonds impregnated inside the metal matrix. Diamonds are furnaces sintered in a matrix made of iron, cobalt, nickel, bronze, copper, tungsten,  alloys of these powders or other metals in various combinations. Metal Bonded Diamond Tools are “impregnated” with diamonds. The compacted materials are then hot pressed or sintered to full density. Heating rate, applied pressure, sintering temperature and holding time, are all controlled according to the matrix composition. This means that selected diamonds are mixed and sintered with specific metal alloys to achieve the best cutting performance possible on any materials such as sapphire, advanced ceramics, optics, glass, granite, tile and etc. The metal bond surrounding the diamonds must wear away to continuously keep re-exposing the diamonds for the diamond tool to continue cutting. Sintered (metal bonded) diamond tools are recommended for machining hard materials from 45 to 75 on Rockwell Scale (5 to 9.5 on mohs scale of hardness). As a general rule of thumb, Metal Bond (sintered) diamond drills last longer than other diamond drills available

They can be used in almost all diamond drilling application ranging from very soft & abrasive materials to ultra hard materials. Typical applications include in order from hardness: Composites, Glass, Concrete, Sandstone/flagstone, Natural Stone, Optical Materials, Precious & Semiprecious stone, Advanced/Technical Ceramics, Advanced Materials, & Many Others. Sintered (metal bonded) diamond drills/bits are used & preferred in most Industrial/Manufacturing, R & D, Professional Contractor, & Serious Hobby Enthusiast / Craftsmen users. Sintered (metal bond) diamond core drills/bits are most widely used diamond drills across almost all industries & applications. They wear evenly, and are known for their long life & consistency. Precision & Accurate tolerances either on OD, ID, Run Out & Concentricity can only be obtained with sintered (metal bond) diamond drills

Sintered (metal bond) diamond core drills/bits Require PROPER USE & SOLID UNDERSTANDING of Proper Diamond Drill/Diamond Tool Principals. Experience well help as well. Careless handling or use in imprecise machinery will result in diamond drill wrecking/breaking, bending or cracking the bond and will prevent future use.

 Drilling life will vary with manufacturer & application/material factors described in this guide below. While there is no way to accurately predicting diamond drill life, with most conventional sintered (metal bonded) diamond drills, you can expect 350 to 1200 holes, parts machined, or cores. In laboratory tests, Diamond Drills with SMART CUT technology have shown to last 2,000+ holes on many applications/materials. Sintered (metal bonded) diamond core drills/bits with SMART CUT technology are the latest technology available in diamond drills. And represent the best value and performance per hole or part.

HYBRID BOND™ Diamond Drills 

Between METAL BOND and RESIN BOND. Designed to produce smoothest surface finish possible. You will find all the advantages of drilling speed and fine finish that you have come to expect in a resin bond, and long life, consistency, aggressiveness, durability, and excellent performance on you look for in a metal bond. Hybrid Bond Diamond Drills are used on finish critical applications, that require a minimum amount of chipping and where no further polishing, lapping, or processing of material is planned. Best performance will be achieved on following applications: Glass/Quartz Tubing, Bk7,  Fused Silica, Other ultra brittle materials. Advantages include: Less Chipping, Additional Universality in Application - 1 drill will work in both metal bond and resin bond applications, and Greater Consistency in Performance.

Electroplated (Nickel Bond) Diamond Drills

Electroplated  Diamond Core  Drills & Electroplated Thin Wall Diamond Core Drills  have a high  diamond  concentration and maximum diamond particle (grit) exposure/protrusion ratio. This provides freer,  faster drilling  action  with  minimum heat generation. Electroplated Diamond Drills provide excellent performance on softer materials ranging from 6 to 1 on mohs scale of hardness. While electroplated diamond drills, specifically manufactured by UKAM Industrial, will still work on  harder materials (up to 9 on mohs scale). Diamond drill life will be (very short) significantly reduced. Diamonds stay on the surface of the drill allowing for fast material removal. Perfect for softer, more ductile, and gummable materials. 

Not recommended for drilling very abrasive materials such as sandstone and concrete (they will wear out on these materials almost immediately). Electroplated Diamond Drills last less than metal bond, hybrid bond drills and are the least expensive diamond drills available. They provide very smooth surface finish quality & less thermal damage to the part being drilled

Electroplated diamond drills are frequently used in glass and composite industries (as well as some photonics / optics) applications. Electroplated Diamond Drills are designed for small & occasional use.  They are widely used by beginning diamond drill users (novices) in numerous hobby/craft applications. As well as home owners and contractors requiring to drill a few holes when installing tile, marble, shower doors, glass mirrors, and etc. (not recommended for professional or serious industrial use). They are also usually more forgiving to operator/user drilling mistakes than most other types of diamond drills/bits. Electroplated core drills are just about the only type of diamond drill that may be used dry (without coolant) in a few applications if needed. Best performance and results will be achieved when drilling less than 1/4" (6.35") into material. Performance in many applications will decline when drilling thicker materials.

Most Electroplated diamond drills/bits have only one layer of diamond coated on a steel body. Diamonds stay only on the surface. When this diamond portion is worn out or peeled off, the diamond drill will slow down, drill on the side (not drill straight) or stop working (drilling) altogether. Electroplated diamond core drills Manufactured by UKAM Industrial are Multi Layered. They have 3 layers of diamonds, not just 1 layer of diamonds like conventional electroplated drills. This provides longer drilling life, faster and freer  drilling action, & more consistent performance. Find out more >>>

Evaluating Diamond Drill/Bit Performance

The performance of a diamond drill/bit for just about any application / material can be evaluated under various criteria. The importance of any criteria depends on your requirements.

Diamond Drill Life - The life of a diamond drill/bit is determined by the number of holes or it can drill (parts machined). It is fairly difficult to estimate the life of diamond drill. Diamond drill life is affected by various factors such as the application, bond type, drill manufacturer, and experience of user in properly using the drill. Diamond drill life will be discussed in further detail in this guide below. The following considerations play a major role in diamond drill life:

  • hardness and abrasiveness of the material being drilled

  • speed and power of drill

  • amount of pressure used (feed rate) 

  • proper use of coolant (type of coolant, coolant force, & direction)

  • Drilling Depth

  • Material Holding Method

  • operator experience (Understanding Proper Diamond Drill Usage Principals and Adjusting them as need to better fit their particular application & objectives)

  • overall age and condition of drilling equipment (precision, accuracy, & repeatability of drilling equipment used)

  • quality, hardness, sharpness, and mesh size of the diamonds

  • hardness of the bond compared to the material being drilled

  • experience and technology of manufacturer in keeping diamonds in the bond

Surface Finish Quality - The quality of the surface finish is evaluated by the amount of chips generated on the face of the material. Surface finish consists of three basic components: form, waviness and roughness. Although there are more then 100 ways to measure a surface and analyze results. A visual check is the most simple & easiest way of measuring (checking) surface finish quality. The most common scientific way of measuring surface finish quality is using Ra, or Arithmetic Average Roughness. It basically reflects the average height of roughness component irregularities from a mean line. Ra provides a simple value for accept/reject decisions.

Break in time - A diamond drill requires time to break in, to produce relatively chip free performance. The period of time under which this occurs, separates one diamond drill/bit from another.

Frequency of Dressing - The less you have to dress your diamond drill, the better off you will be.


How many holes will this diamond drill last? 

Why did my diamond drill wear out after only ....

the list of questions goes on. These are just some of the typical questions that our engineering staff answers every day. To help you better understand the factors & variables that play a major role in life/performance of your diamond drill/bit we have written an explanation below. We hope you will find this guide helpful.

Material Hardness + Density + Drilling Depth + Material Shape/Geometry + RPM's + Feed Rate + Coolant Used + Drilling Equipment Type/Condition + Material Holding Method + Operator Experience 


Diamond Drill Life & Overall Performance will vary with material hardness, density, Drilling Depth. Few other factors that play a role in diamond drill life include: RPM's (drilling speed), Feed Rate, Geometry (shape) of Material, Coolant being Used, Coolant feed rate and Direction. Drilling Equipment, Material Clamping Method & experience of operator. While there is now way of accurately predicting Life of your diamond drill. It can be optimized by following Principals of Proper Diamond Drill / Tool Usage. There may also be some experimenting, as well as trial & error involved in the part of the end user. Highly experienced diamond drill users may find some variations in diamond drill life or performance even when working on same material & application for several years. While this phenomena is not too common, it does occur. The machining environment around us is constantly changing. A slight change or variation in any variable can have significant impact on your diamond drilling results. Material being drilled can vary in composition or density even when coming from same manufacturer or source. Slight change in coolant feed rate, coolant direction, RPM's, even the way the material is held in place can make the difference. Frequently the cause of the problem may not be obvious and may take as much as several failed attempts to surface. Fore more information on optimizing your Diamond Drilling Operation to ultimate level of performance >>>

When encountering problems or variation in diamond drill performance. Few stop to think about or carefully examine their drilling process. Many users immediately suspect quality of the diamond drill and are quick in labeling the drill "Defective" or "Poor Quality". This is very rarely the case. Usually in over 90% of these cases the diamond drill itself was not at fault. Most Respectable & Experienced Diamond Drill Manufactures have rigid quality control and inspection processes set in place. Controlling everything from raw material input, output, to final inspection. What a number of diamond drill users don't realize the technical aspects & delicate nature of diamond drilling/machining process. Unlike carbide, high speed steel, & other types of drills. Diamond drill works by grinds away material on micro (nano) level. Carbide and other types drills on the other hand cut material with a sharp cutting edge. A simple example of the minute details and understanding that play a major role in your diamond drilling process. What is important to understand is that almost all diamond drill/bit users, regardless of experience or technical background will make some type of an unintended operator error while using their diamond drills/bits. With this in mind, UKAM Industrial Superhard Tools has assembled a list of most common diamond drill operator errors made by users in all industries & applications. Looking through this guide will help you  RESOLVE MOST COMMON DIFFICULTIES  you may have in using your diamond drills/bits, as well as  AVOID MOST COMMON PROBLEMS  in the first placeDIAMOND DRILL / BIT TROUBLESHOOTING GUIDE >>>

Selecting the Right Drilling Equipment 

for your Diamond Drill/Bit & Application

Diamond Core Drills can be used on a wide variety of equipment, such as: Drill Press, Hand Held Drill, Angle Grinder, CNC & Milling Machines. For most applications we recommend a you use diamond drills on a drill press. The drill press provides uniform drilling consistency, tighter tolerances, and better overall performance. Although a drill press may cost you more than an angle grinder, hand held grinder, or hand held drill. It will pay of in the long run.

Although there are hundreds of different types of drill presses on the market. For the most part, drill presses can be classified as two different types:

Bench Drill Press - Used for smaller jobs. Usually bolted or clamped to table or bench top or stand. This is the smallest and least expensive type of drill press. Perfect for the hobbyist and beginner.

Floor Drill Press - Larger drill press. Usually has a base that stands directly on the floor of your shop. This drill press can be extended and adjusted for optimum use and movement. An operator may use this drill press in either sitting or standing position. This type of drill press can be found used in most machine shops and professional hobbyist.  

Industrial / Production Drill Press - Heavy Duty type of drill press, similar to a milling machine. Usually come with adjusted RPM (variable speed), larger drilling table (area) for holding larger parts (material), more powerful motor, capability to use chuck or collet, move drilling head up and down, move table horizontally and vertically. 

Specialty / Custom Drill Press - Manufactured for specific material / application. For example, when machining very abrasive materials the drill press will be made from special type of metal to minimize dust and corrosion. Come with ultra precise chucks, collets, water pumps and devices. With these types of drill press you are usually able to regulate drilling depth either electronically or by computer, maintain consistent speed and feed rate. More advanced drill presses today may have feed back mechanism that provides information on all of these variables. 

Before Buying a Diamond Drill or Drill Press

When buying a Diamond Drill to fit your current Drill Press or buying a Drill Press to fit a Diamond Drill, we recommend you carefully examine both drill and drilling equipment specifications to make sure they are compatible. Some variables you should consider:

Motor - Drill presses run on electric motors rated in horsepower. Make sure the motor for the drill press you choose is powerful enough for the material you are planning to drill and the diamond drill you are planning to use. Most Bench Drill Presses have motors rated between .3 hp and .5 hp. Floor Drill Presses on the other hand have motors that run between .75 hp and 1.5 hp. We recommend you choose the highest power motor you can afford. Doing so will place less strain on your job and will allow you to be more flexible, if you decide to use another drill or drill a different type of material in the future.

Speed Control -  You will need to adjust the speed (RPM) at which you diamond drills run, depending on the material you are planning to drill. A drill press will usually allow you to run your diamond drills between 500 RPM (Revoltutions Per Minute) to 3,500 RPM. Some Drill Presses only provide specific speed settings, such as 500, 1,000, 1,500, 2,00, 2,500, and 3,000 RPM. This may be acceptable to you, again depending on the diameter of the diamond drill and material you are planning to use it on. Before buying a drill press, make sure it will run at the Recommended RPM set for your diamond drills.

Throat Depth - Drill Press design usually limits the distance between the center of the spindle (where the diamond drill is placed) and front edge of the vertical post that is used to support the drill head. This is called the throat depth. When drilling a hole in the center of a round work piece such as a tabletop, the radius of your work piece will need to be less than the throat depth itself.

Spindle Travel - The spindle of a drill press moves up and down only a certain distance. The distance the spindle can move is called spindle travel. This determines the maximum depth of the holes you will be able to drill. The drilling depth of your diamond drill will need to reflect and consider the spindle travel of your drill press.

Table Adjustments - Most Drill Presses have a tilting worktable. Some have the capability to tilt 45 degrees left and 45 degrees right. Others can tilt a full 90 degrees in each direction. Before buying a drill press, make sure the model you are considering, can work with the angles you need to make for your application. It is also recommended that the table swing in the horizontal pane as well. An excellent type of drill press is the on that can spin completely around the post.

Head Adjustments - A number of Drill Presses supplement a tilting table with a tilting drill head. Tilting heads typically move 45 degrees left and right, and ease the mind-bending work of compound angles. We recommend you are comfortable with both the adjustment mechanism and the angle gauge before using or buying this type of drill press.

Drill Press Accessories - There are a number of accessories on the market that will make your drilling experience faster, easier, and provide better performance as well as lower cost per hole. A few important ones include:

  • Water Swivel Adapters - used to supply water through the center of your drills. Increase drill life 40% to 75%, improve quality of hole, and surface finish.

  • Shank Adapters - thread into your diamond drill collet, and allow the diamond drill to be placed in the drill press chuck.

  • Vises and Clamps - Designed for your drill press worktable. Hold you material firmly in place while drilling.

Hand Held Drills

Nothing beats the versatility and ease of use of a Hand Held Drill. Lightweight and portable, the hand held drill can be taken with you anywhere you go. Perfect for use on horizontal surfaces, and outside jobs. An excellent tool for beginning hobbyist, homeowner and construction contractor. Use a hand held drill where a drill press is not feasible.

Hand Held Drills are available in a wide selection of both corded electric and battery-powered cordless models. The drill type you choose will effect your drilling capability in terms of material and diameter of the hole. The first step in selecting the right hand held drill for your application is determining the size of holes you need to drill and in what materials will you are planning to drill.

Make sure you select the hand held drill that actually has the capacity to do the work you need. Doing so will make your jobs faster and easier. As well as avoid problems such as ruining the diamond drill or material, caused by drilling with the wrong hand held drill or hand held rill without enough capacity. 

The following are some of the features you should consider when choosing the right hand held drill for your application:


A hand held drill's capacity indicates the largest hole size you can drill. Most hand held drills are ranked according to the maximum diamond drill shank the chuck can hold. Most popular drill shank sizes are 3/8" and 1/2". 


Make sure your hand held drill has enough power to use the diamond drill at the recommend RPM. Hand held drills are ranked according to maximum horsepower the motor can give. If your hand held drill does not have enough power, your chuck capacity will be irrelevant. And you will not be able to drill the size of hole and material you need. Before buying a hand held drill, we recommend you compare the horsepower of the drill. By the same token, if you will be working only with small, or soft material, and need to drill only a few holes an inexpensive drill will probably be sufficient for your application. However, if you are planning to drill a large amount of holes, drill hard materials, or make deep holes and need to use your drill often, a more heavy duty and higher powered drill will be required.

When drilling, never force your hand held drills, doing causes a more wear and tear on your drill, than associated with normal usage. Hence, decreasing your machines life and deteriorating future performance.

Angle / Hand Held Grinders

Angle / Hand Held Grinder offers the advantage of low cost, and increasing versatility. With this one piece equipment you can drill, cut, grind, and polish. An angle grinder is excellent choice for small jobs, outside jobs, drilling hard to reach places, or when drilling a very large piece of material. Where using a conventional drill press is not feasible.

CNC / Milling Machine

The best drilling results, precision tolerances, surface finish, and consistency will be obtained on a CNC / Milling Machine. An ideal choice for high production drilling operations. This equipment is fully automatic and controlled by a computer. And costs more than other types of drilling equipment.

What you should know before you buy your next diamond drill?





UKAM Industrial Superhard Tools   Division of LEL Diamond Tools International, Inc.

28231 Avenue Crocker, Unit 80  Valencia, CA 91355  Phone: (661) 257-2288  Fax: (661) 257-3833


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