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 To do this they should be used in short bursts and the whole bit should be regularly withdrawn from the hole and exposed to the air to disperse any heat.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. 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. 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. Due to the amount of heat created during the drilling process it is necessary to keep diamond core bits as cool as possible to prevent unnecessary damage to the cutting teeth to a minimum. If the surface of the cutting teeth are subjected to too much heat the metal encasing them melts covering the diamonds and reducing cutting efficiency. If this happens the drill bit then needs to be “redressed” to expose the diamonds once more.

In the majority of domestic cases the largest hole you will need to drill will probably be around 6 inches in diameter through a standard cavity wall which will be around 300mm in depth. For anything up to this size a dry cutting diamond core bit will be more than up to the job. 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.

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. 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.

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. As we have briefly touched on, a core drill is a drill bit which cuts large holes through masonry and concrete removing the centre part of the hole (core) as it drills and cuts its way through. 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. 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.

Sign up for special offer emails

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. 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.