Amtech F1210 50mm (2") Core drill

Product Information

There are in fact two different types of diamond core bit – wet cut and dry cut. Essentially, wet cut diamond core bits use water to cool them while drilling and dry diamond core bits are just used dry. For example, smaller holes up to 30mm in diameter can be drilled at up to around 3000 rpm whereas large holes around 400mm should be drilled at speeds as low as 300rpm. In general, a corded drill is the best to go for as it will produce power at a more constant rate, but if funds are available, the more expensive and higher quality cordless drills (minimum 24v) from brands such as DeWalt, Makita, Milwaukee etc should provide more than enough grunt. A core drill should always be used with a power drill, at minimum around 800 watts and at maximum somewhere around 1300 watts. Your chosen drill should also have a variable speed function (somewhere between 100 and 300 rpm) and it must also have a safety clutch!

Individual Diamond Cores | Core Drill Bits | Screwfix Individual Diamond Cores | Core Drill Bits | Screwfix

The drill bit itself features carbide “teeth” that surround the circumference of the drill bit. Once rotating, these teeth bite into the surface you’re working on and cut their way through creating the required hole. The best tool to use for this is a cable and pipe detector. You simply pass it over the surface of the wall and if any items such as these are found, lights and/or a buzzer indicate their presence. How to Drill a Hole using a Core Drill With the drill held straight and true, keep drilling, stopping regularly and withdrawing the bit from the hole to allow it to cool down. When withdrawing a core bit from a hole ensure that it is still rotating. Essentially the speed that you drill at will be dictated to you by the size of hole you are drilling. As a very general rule of thumb, the larger the hole you are drilling and the denser the material you are drilling through, the slower the speed you should drill at.When hiring or buying a core bit always make sure you have the correct size and type of arbor for not only the core bit your are using but also for the type of drill you have e.g. SDS, spline, straight shank etc. As well as wearing the drill bit out much faster, the hammer action also creates a lot of vibration whilst drilling often leading to the hole ending up larger than intended. As we have already stated but will do so again, never use hammer action when core drilling. The drilling action needs to be as smooth as possible and the jerky action of the hammer can snap expensive diamond teeth very easily. Mark the Exact Drilling Spot

Core Drill Bit Kit 3 Core | Toolstation TCT Core Drill Bit Kit 3 Core | Toolstation

With the above in mind, dry cutting diamond core bits are generally used when working indoors, whereas wet cutting bits are used externally. When drilling your hole, always hold the drill and core bit dead level. You do not want to drill in at an angle and cause the hole to slope up or down! Once you have cut 25-30mm into the surface you are working on, you can withdraw the core bit and remove the guide drill and carry on without it.Generally, the guide or pilot bit is just used to get you started and keep the actual core bit in position whilst cutting into the surface of the wall. Most domestic use diamond core cutters will always have a removable guiding drill bit which acts as a pilot hole to guide the core drill. If you keep forcing the core cutter through, when you actually break through you will force a large amount masonry away from the outside of the hole, making a total mess of it all. If in any doubt always refer to the manufacturers instructions for your particular power drill and also for the core bit you are using. In both cases, each set of instructions should state the correct drilling speed you should be using. Preparing for Drilling Holes Using a Core Drill If you don’t already have a suitable drill, any decent hire company will gladly supply not only the correct drill but also the correct diamond core bit, if purchasing either the drill or core bit is deemed too expensive. Remember you will also be charged for the amount of wear on diamond tipped bits.

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Once the core bit is attached to the arbour insert the pilot or guide drill into the arbour, pushing it in until it goes tight. Unlike carbide drill bits, the teeth on a diamond core bit features diamonds that are embedded in the teeth themselves. As diamonds are extremely hard they grind their way through the surface you’re working on creating a sharp and clean cut. Keep drilling until the core drill teeth hit the surface of the wall. You will feel them bite once they do. However, leaving it in will allow you to see when it is about to break through the opposing side of the wall you’re drilling through. More about this and why this is a good thing can be found below. Before you start your drilling you should always make sure there are no cables or pipes hidden in the wall at the spot you intend to drill your hole.Corded power drill with safety clutch and variable speed ideal for use with a core drill How Fast Should you Drill When Using Core Bits? Although it is not recommended, many use hammer action with these drill bits to increase their cutting speed and ability. This will ultimately wear the core bit out much faster, but as they are generally cheap this is not often seen as a major concern. There are a few different types of core bit and the best one to use will very much depend on the size and depth of hole you’re drilling and the type of material you are drilling through. You can never take it for granted that work hasn’t been done by someone else in this area before and it has not been recorded.

core bits - Hilti GB Diamond core bits - Hilti GB

For the neatest cut and finish to your hole it is advisable to then finish the hole from the other side. This guarantees both a neat entry and exit hole. If however the depth of the hole is longer than the drill bit you will need to withdraw the core bit when you hit a depth of about 125-130mm and chop out the core with a hammer and bolster, or in some cases you can lever it out.

Preparing for Drilling Holes Using a Core Drill

As this point it’s a good idea to ask someone to stand on the other side of the wall and let you know as soon as the guide drill breaks through and when it does, stop drilling. Keep a close eye on your drilling depth and once you are roughly within and inch of breaking through the wall on the other side, decrease any pressure and also speed slightly. If you are able to drill right the way through the wall in one go, the core drill will remove the core at exit.