How Do You Use A Rotary Hammer?

How Do You Use A Rotary Hammer

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It’s fairly simple to use a rotary hammer. Despite its size and bulk, a rotary hammer is actually one of the easier power tools to use in terms of simplicity. Almost all rotary hammers in the market today uses a simple insert, twist and lock system for installing and removing drill bits and attachments.

Combine the  a built-in mechanism for shock absorption, the relative lack of teeth or extremely sharp points in most rotary hammer bits, plus the fact that rotary hammers do not spin very fast to begin with, and you actually have one of the safer tools you can pick up and use.

Rotary hammers are the power tools of choice when it comes to drilling holes in concrete, masonry, packed dirt, and even stone. They are heavy-duty impact tools that are designed to deliver impressive amounts of impact power at high rates (blows per minute), so even if rotary hammers are at the lower end of the scale when it comes to their rotational speed and torque, they are particularly suited for breaking into very hard, brittle materials.

 A rotary hammer drill bit is made to pulverize, rather than cut into the material being drilled, and this makes them the perfect tool to have for drilling through-holes in concrete walls or drilling receptacles for anchor bolts in concrete slabs.

Most rotary hammers also have three modes of operation: “drill and hammer,” “drill only”, and “hammer only modes. In this guide, we go into a review of the basics of using a drill hammer, before moving on to a more detailed look at the usage and recommended applications for each of these three rotary hammer settings.

How to Use a Rotary Hammer Drill

To use a rotary hammer drill, or a rotary hammer for short, first you have to consider the task at hand. Will you need to drill holes in concrete? How wide and how deep do these holes have to be?

Or perhaps you need you rotary drill for something else, such as for pounding grounding rods into the ground or stripping ceramic tiles off of a concrete slab. Depending on the application, you will need to first install the right drill bit or tool attachment to your rotary hammer.

Speaking of drill bits and tool attachments, rotary hammer and the bits and tools that go into them generally use three systems – the SDS Plus, the SDS Max and the Spline. All three systems are installed the same way – you simply insert the hammer into the tool.

For SDS Plus and SDS Max rotary hammers, you may need to push back the chuck towards the rear of the tool, and hold it while inserting the drill bit. Give the drill bit a twist, and a spring loaded retainer will lock the bit in place.

You can then release the chuck and give the bit a tug or two to check that it’s been secured properly. Rotary hammer chucks and bits are designed to move along the shaft axis of the tool, so you should expect the bit to move forwards or backwards just a little as you tug on it.

For rotary hammers that use the Spline system, the spline bits have 12 grooves or ridges that are precisely milled to exact tolerances. To install a Spline bit, insert it into the tool and give it a twist until the bit seats properly – you will feel or even hear a retaining pin engage the spline section of the shank, which will tell you that the Spline bit has been properly secured.

If you’re using a bit or tool attachment for the first time, it’s always a good habit to grease it first – more information on the greasing process later. It’s always a good idea to put on some personal protection before using a rotary hammer, especially if you are drilling into a wall or overhead, where debris can get to your face.

Use eye protection whenever possible, and invest in a good mask if you are drilling in a dusty environment. Hand protection and sturdy plated shoes are recommended as well.

Once you have the bit or tool attachment installed, connect your rotary hammer to its power source - plug it in an outlet, or attach a charged battery to it. Confirm that you have the right rotary hammer setting for the job and the bit you have attached: “drill and hammer” for drilling into concrete, or “hammer only” for chiseling, to give a couple of examples.

Some rotary hammers also come with rotatable chucks that lock at the current angle when the tool is in use. If you are using a chisel on your rotary hammer, this lets you set the chisel at the proper angle before you start chiseling.

If you are drilling holes at a certain depth, now is the time to adjust your depth gauge, too. Most of the depth gauges on rotary hammers are attached on a removable secondary handle that goes near the chuck of the tool, so if you haven’t already installed the handle, put it on before you start drilling. Then, set the depth gauge stick to the right depth.

Point the tip of the drill bit to the target area, and take a second to find your footing. For drilling holes into concrete, it often helps to set the tool to “drill only” mode to make a pilot hole. Then once the bit is nicely settled into a pilot hole, you can switch to “hammer and drill” to drill the rest of the way.

How to Install a Bit on a Rotary Hammer (SDS and Other Bits)

A rotary hammer is only as good as the drill bit (or tool attachment) that it comes with, and the first thing you will need to do before you can use your tool is to load it up with the bit you want.

You may have a rotary hammer with an SDS or SDS Plus adapter that takes the smaller 10 mm diameter shank bits, or you may have a tool with a larger SDS Max adapter to go with your 18 mm diameter shank bits. Perhaps you may even have an older tool with a Spline adapter that takes Spline bits. 

The way to install your bits on these systems remains basically the same. First, you need to hold the chuck at the front of the tool and push it towards the rear. Then, while holding the chuck in place, pick up your bit with your other hand and insert it into the chuck. Give it a twist, until it slides all the way in and you hear it hit the seat of the chuck. You can then release the chuck and check if the bit is properly secured.

Give the bit a tug or two to make sure that it is properly attached to your rotary hammer. It’s perfectly normal for the bit to have some “play” in it while pulling it out of the tool – the bits are designed to move as the piston hammers into them, and this also isolates the rest of the tool (and your hands) from all that vibration.

You can use an SDS rotary drill bit with an SDS Plus tool, and the other way around – both systems are compatible with each other. If you want to use an SDS Plus or Spline bit with an SDS Max tool, on the other hand, first you need to use a bit adapter.

Insert the SDS Plus or Spline bit into the appropriate adapter using the same process  - push back the adapter chuck, insert, twist, and release. Then, you can now insert the adapter shank into the SDS Max tool, and you will be able to use your rotary hammer bit as usual.

How to Remove Rotary Hammer Drill bit

Once you have finished drilling, wait for a few seconds to let the drill bit get a chance to cool down first, before touching it with your hands. Then remove the drill bit the same way you put it in – push the chuck back, twist the bit and pull it free. Make sure to clean moisture, grit and debris from your drill bit before storing it.

Sometimes, the drill bit can bind up in a hole and get stuck. This may happen if you try pushing the drill bit into the hole with too much pressure – the pressure slows down the drill bit, and if it gets slowed down too much, the flutes don’t get the chance to clear the debris. The result is a drill bit stuck in a bed of compacted debris and half-drilled concrete.

Some rotary hammers have a reverse setting – in this case, use that to try to reverse the bit out of the hole. If the drill bit is still stuck, then you can try pulling it out with a wrench. Detach the rotary hammer drill bit by pushing the chuck of the tool back, then twisting and pulling the tool free. Then gently use a wrench to work the drill bit out of the hole – use just enough pressure to get the bit to turn in the reverse direction, so the bit can be gradually brought out.

Drill bits that have become too dull are also more prone to binding. Check that your bits are in good condition before using them to drill deep holes in concrete. It also helps if you occasionally pull out the bit to clear the hole of excess concrete dust as well.

How to Properly Grease a Rotary Hammer

It’s always a good idea to grease new bits before inserting them in your rotary hammer. It not only helps you install and remove them easier, it also protects the chuck system. The result is a tool that lasts longer. To properly grease a rotary hammer, you need to keep three things in mind.

First, grease a shaft only after cleaning it. The grease tends to trap dirt and grit, which will be harder to clean out of a greasy shaft. Second, use only the grease recommended by the manufacturer. Other substances may cause damage to the plastic or rubber in the chuck.

Third is to watch the amount of grease you apply – you only need a smear. Too much grease means that the shaft and the chuck may gunk up from accumulated debris and lubrication. Use only enough grease to let you insert the shank easily.

Rotary Hammer Settings

Rotary hammers often come with three settings: “Drill and Hammer”, “Hammer Only” and “Drill Only” modes. Most models come with a dial within easy so you can change the modes anytime.

“Drill and Hammer” mode is the most useful for drilling holes into concrete and brick. If you do find yourself using your rotary hammer for drilling into wood (widening holes, for example), there’s usually a “Drill only” mode for that.

Special tools like chisels, spades, and scaling tools are designed to be used with the “Hammer Only” or “Impact Only” mode of a rotary hammer.

Rotary Hammer Drill Function

Many rotary hammers can be set to a “drill only” mode, which disengages the impact mechanism. Set your rotary hammer to this mode to use it for mixing, drilling through wood and steel, or for using it as a soil cultivator with an auger bit.

Hammer Function

Rotary hammers also offer a “hammer only” mode, where the shaft does not rotate – making the tool something of a mini-jackhammer. Use this mode for chisels, spikes and tamping heads to chisel away or hammer at surfaces. You can also use the hammer function with a grounding rod attachment to drive rods into the ground.

Hammer/Drill Function

This is the default setting for rotary hammers. A “hammer and drill” function works best for drilling into concrete, masonry, rock and packed clay. This setting will also let you use core bits and coring tools more efficiently, as well.

To see which of these modes are currently selected for your tool, check the mode selector dial which is on the side of the tool on most models. Some manufacturers use icons to indicate the setting – to see what these icons mean, check the user’s manual.

For most drilling tasks, having a regular drill or even a hammer drill lets you cover just about everything – except when it comes to concrete walls and masonry.

For bigger jobs that require you to drill inch-wide holes through solid concrete wells, or gouge out a bore through a thick concrete slab, a rotary hammer is the undisputed tool for the job. Rotary hammers do not spin all that fast, but when it comes to concrete, a high RPM can only help you so much. 

Rotary hammers are instead designed to hammer into and pulverize the material with the help of a powered piston, which makes them the top pick when it comes to breaking through foundations and drilling through-holes right through brick walls.

They pack a quite a punch, and just like you would expect, they are heavy, hefty tools that require you to use two hands and maintain a solid footing. Here are a few tips to for safe and efficient drilling that makes the most out of your rotary hammer.

Surfaces That You Can Use a Rotary Hammer On

Rotary hammers are tools designed to efficiently work on dense, hard surfaces - concrete, brick, building blocks or masonry. They also do well when used on rocks and packed ground, as well.

With the proper bits, they can also be used to split marble and granite boulders, too.  Their low RPM makes them less than ideal for drilling into wood or steel, though.

How to Use a Rotary Hammer on Vertical Surfaces (Walls, Columns, or Posts)

First, install the drill bit or tool on your rotary hammer. Grease the bit shank first if you have to, then push the chuck back, hold it while inserting and twisting the bit, and let go after the bit clicks in place. It’s always a good idea to make it a habit to give the bit a tug or two, just to check that it’s safely secured.

Put on your safety gear – at the very least, put on safety glasses and a pair of gloves. Make sure that the rotary hammer cord is safely out of the way, and the same goes for your hair or any loose article of clothing on you.

Check that the rotary hammer setting is properly set for the job. Drilling holes call for a “drill and hammer” setting while using chisels and scaling tools require a “hammer only” mode to be selected.

Hold the tool with both hands, and aim the rotary hammer bit at the vertical surface. Make sure your footing is stable. If you are working on a ladder, check that you are at a comfortable distance from your target spot.

Hold the drill bit against the wall, and press the trigger. Keep the drill bit on the same spot until it digs in, but do not apply too much force. Let the rotary hammer do most of the work – your role is to keep it aimed straight and securely held.

Once you have finished drilling the hole, wait for the drill bit to cool down first before handling it. Remove the bit and disconnect the rotary hammer from its power source before storing it in a safe place after use.

How to Use a Rotary Hammer on Horizontal Surfaces (Ground and Floors)

Using your rotary hammer on a horizontal surface is somewhat easier than holding it up against the wall – you can let the weight of the tool work with you, not against you. That said, you still need to pay attention to your tool if you are to keep your holes straight.

Put on the drill bit or tool accessory you need for the task at hand. For putting in small anchor bolts, a smaller SDS or SDS Plus bit will do well. For putting in lag bolts and the like, the longer 16-inch bits are generally the preferred choice. Grease the shank if you need to, especially if you are using a bit for the first time with a tool.

Put on your safety gear, and this should include eye protection, at the very least. Rotary hammers are relatively safe tools with low RPMs, but eye protection is generally cheap, widely available and easily replaced that it’s a tiny investment to protect yourself from the worst case scenario. When drilling into the ground, it also helps if you have decent feet protection to go with a sturdy pair of work pants, as well.

Check that the rotary hammer is at the proper setting for the job – “drill and hammer” for drilling holes, “hammer only” for chipping and digging.

Aim the rotary hammer bit into the target spot, and use both hands to steady the tool. Press the trigger, and hold the tool in place while gently pushing it in – let the tool do the work for you.

Once you’re done drilling your holes, let the bit cool down before releasing and cleaning it as needed. Disconnect your tool from the power source and store it properly after use.

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About the author

Ryan

I have been in construction nearly my entire life and have a fascination with tools and love when they make my life easier. Match that with my "research addiction" and you create something like this website!

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