Our guide to the best drill bits: How to know what drill bit to use

Posted by John Rennie on

Choosing the right drill bit for the right project is vital to the success of the finished product. If you choose the wrong drill bit, you risk both the integrity of the project itself, and damage to your equipment.

To make it easier for you, we have put together this simple guide to choosing the best drill bits. The Rennie Tool Company is dedicated to ensuring you have access to the best advice, and the best products on the market, and if there are any questions here that remain unanswered in ascertaining which drill bit to use, then we are happy to advise you accordingly.

Firstly, let’s state the absolute obvious – what is drilling? We believe that establishing exactly what we mean by drilling will put you in the right mindset to understand your drill bit needs more precisely.

Drilling refers to the cutting process of solid materials using rotations to create a hole for a cross-section. Without drilling a hole, you risk splitting and damaging the material you are working with. Equally, you need to make sure you only use the best quality drill bits. Do not compromise on quality. It will cost you more in the long term.

The actual drill bit is the tool that is fixed into your piece of equipment. As well as having a good understanding of the material you are working with, you need to assess the accuracy required of the job at hand. Some jobs require a higher degree of accuracy than others.

Whatever the material you are working with, here is our comprehensive guide to the best drill bits.

Drill bits for wood

Because wood and timber are relatively soft materials, they can be prone to splitting. A drill bit for wood enables you to cut through with minimal force, minimising any risk of damage.

Formwork and installation HSS drill bits are available in long and extra-long lengths as they are ideal for drilling in multilayer or sandwich materials. Manufactured to DIN 7490, these HSS drill bits are particularly popular with those in the general building trade, interior fitters, plumbers, heating engineers, and electricians. They are suitable for the full range of timber materials, including formwork, hard/solid wood, softwood, planks, boards, plasterboard, light building materials, aluminium, and ferrous materials.

HSS drills bits also give a very clean, fast cut through most types of soft and hardwood
For CNC router machines we would recommend using TCT tipped dowel drill bits

Drill bits for metal

Typically, the best drill bits to choose for metal are HSS Cobalt or HSS coated with titanium nitride or a similar substance to prevent wear and damage.

Our HSS Cobalt Step drill bit on a hex shank is manufactured in M35 alloyed HSS steel with 5% cobalt content. It is particularly ideal for hard metal drilling applications such as stainless steel, Cr-Ni, and special acid-resistant steels.

For lighter nonferrous materials and hard plastics, the HSS Titanium Coated Step Drill will provide sufficient drilling power, though it is recommended to use a cooling agent where necessary.

Solid Carbide Jobber Drill bits are used specifically for metal, cast steel, cast iron, titanium, nickel alloy, and aluminium.

The HSS Cobalt Blacksmith reduced shank drills is a heavyweight in the metal drilling world. It eats its way through steel, high tensile steel, up to 1.400/mm2, cast steel, cast iron, nonferrous materials, and hard plastics.

Drill bits for stone and masonry

Drill bits for stone also include bits for concrete and brick. Typically, these drill bits are manufactured from tungsten carbide for added strength and resilience. The TCT Tipped Masonry Drill sets are the workhouse of our drill bits and are ideal for drilling masonry, brick and blockwork, and stone. They penetrate easily, leaving a clean hole.

The SDS Max Hammer Drill Bit is manufactured with a Tungsten Carbide cross tip, producing a fully hardened high-performance hammer drill bit that is suitable for granite, concrete, and masonry.

Drill bit sizes

Awareness of the different elements of your drill bit will help you choose the right size and shape for the job at hand.

The shank is the portion of the drill bit that is secured in your piece of equipment.

The flutes are the spiral element of the drill bit and help displace the materials as the drill works its way through the material.

The spur is the pointy end of the drill bit and helps you to pinpoint the exact spot where the hole needs to be drilled.

As the drill bit turns, the cutting lips establish a hold on the material and dig down into the process of making a hole.

When you work in the trades, the investment you make in your equipment is significant. If chosen well, your tools can last you a lifetime, and beyond. Make sure that you put time and effort into researching what the best drill bits are for the job at hand. It will help to prolong the lifespan of your equipment and contribute to a better overall result on your job. Similarly, should you still be unsure about which drill bit is best, you can always contact us via 0161 477 9577 or esales@rennietool.co.uk

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