Diamond core drill and correct sized arbour What Type of Power Drill do you Need for Core Drilling?

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. 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. 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! With everything assembled it’s time to start drilling your hole. Position the tip of the guide drill on your drilling mark and start the drill slowly, increasing speed slightly until the pilot drill starts biting into the wall. 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.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. 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. Again, as we have also touched on above, there are several different types of core bit available and depending on the object you are drilling through and the size of hole you need to create will ultimately depend on what type of core drill your should use. Carbide Core Drill Bits

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. 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. 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 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. Drilling a 6mm hole in the wrong place can easily be rectified, but trying to fill in a 4 inch hole is not an easy job at all.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. 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. Before you start any drilling, the first job is to measure and mark the exact spot that you want to drill your hole so there isn’t any mistakes. 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. With the drilling point clearly marked on the wall, next setup your core bit and drill. Screw the arbour into the end of the core bit until it’s pinch tight.

At this point you will only have around half an inch or so to drill through so take your time and once done you will be left with a nice neat and clean 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 When using dry cutting bits it is essential that they are kept as cool as possible. To do this they should be used in short bursts and the whole bit should be regularly withdrawn from the hole and exposed to the air to disperse any heat. Despite this, dry cutting diamond core bits don’t have to be used dry you can also use them wet. 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.

How Fast Should you Drill When Using Core Bits?

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. 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. 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 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. 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!