Tips for drilling stone
Tip 1: choose the right drill bit
Every drill job needs the right drill bit. Have you ever tried drilling wood with a stone drill bit? The result won't make you happy. The same is true for drilling stone. If you try it with a metal drill bit, you won't get much further than a little chip in a brick or the mortar. A stone drill bit is the only right accessory for this job. This type of drill bit has a blunt head with wings that smash the stone. Consider your drill's chuck mechanism (quick release or an SDS version) when you purchase a stone drill. It determines how the drill bit is held.
Tip 2: impact or no impact
You can practically poke a hole in porous concrete with just a screwdriver. Granite and marble on the other hand are very hard. Limestone and sandstone are somewhere in between in terms of hardness. When drilling the harder stone types, you'll be tempted to switch on your impact drill's impact function. Be careful with it though. Not that's there's anything wrong with impact drilling; your drill has the option for a reason after all. Just don't use this function until you're sure that just rotation won't give you the result you're looking for. If you do use it, slowly increase the number of impacts. Damaging the stone happens quicker than you might think and is always difficult to repair.
Tip 3: drilling into stone or into the joint?
If you want to drill brick, or rather a brick wall, you'll have to decide between drilling into the actual brick or into the joint. Both have their advantages, if you're not already forced to choose 1 of the 2 based on an exact height for instance. Drill into the brick if you're going for load capacity for heavy objects. In that case, it's best to drill in the middle of the brick. The advantage of drilling into the joint (note: less load capacity) is that it's quicker and easier to patch up later. In both cases, use a depth stop (or marking on the drill bit) to prevent you from drilling too deeply.
Tip 4: plugs and screws
A plug provides anchoring for a screw you want to put in a stone wall. The end of the plug expands when you screw in the screw, making sure it's in their securely. Not using a plug when drilling stone really isn't an option. The screw won't have any grip. For the diameter of the drill hole, you have to consider the diameter of the plug you want to place the screw in. Use a depth stop to make sure the plug is flush with the hole. Gently tap it into the clean drill hole with a hammer (if you can't push it all the way in with just your finger).
Tip 5: look out for pipes
Drilling into a wall can be a bit unnerving when you're not sure where the pipes and wiring are. Unless you've built the wall yourself or have some idea of where your water pipes and electrical wires are, it's a good idea to find out. Better to be safe than sorry! It's a cliché, but for good reason. If you use a pipe locator, you'll know exactly where it's safe to drill and particularly where it's not. They'll detect current or metal and tell you if you can drill. Who wants to end up with wet socks for trying to hang a cabinet?
Tip 6: get rid of dust
Drilling stone can be a messy job with all the dust and grit. That's why it's sensible to recruit a helping hand who'll hold the vacuum under the drill bit. At my house, I always get one of the kids to do it, since they love helping out their old man. In addition to keeping your floors clean, it's also important for the quality of the drill hole. By pulling back the drill occasionally during drilling, you can keep the hole as clean as possible. All done? Make sure to vacuum the hole so the plug will fit neatly.