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. 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 To do this they should be used in short bursts and the whole bit should be regularly withdrawn from the hole and exposed to the air to disperse any heat.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.

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! 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.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. 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. 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. With the above in mind, dry cutting diamond core bits are generally used when working indoors, whereas wet cutting bits are used externally.

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. Keep drilling until the core drill teeth hit the surface of the wall. You will feel them bite once they do. 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.

How to Drill a Hole using a Core Drill

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. 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. 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.

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. Diamond core drill and correct sized arbour What Type of Power Drill do you Need for Core Drilling? 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.If you are able to drill right the way through the wall in one go, the core drill will remove the core at exit. 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. Trying to drill more dense objects such as solid concrete will in most cases cause the bit to heat up, wearing it out even faster.

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. 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. 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. 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! 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.

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. 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. 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.