Many times there will arise a need for holes that need to be drilled into some sort of masonry and/or concrete materials and for large jobs that need a lot of holes done over the course of a day, your ordinary drill is simply not up to that kind of workload.
If you need a lot of large holes drilled, even your hammer drill will get pushed past its limits. These kinds of jobs are best left to the rotary hammer, which can drill large holes in concrete all day, every day.
Aside from drilling holes, rotary hammers shine when it comes to demolition jobs. With a suitable attachment, you can convert your rotary hammer into a heavy duty tool that can break up concrete, chisel away tile and even soften packed soil.
Rotary Hammer & Hammer Drill Hammering Action Differences:
It’s easy to confuse the two power tools, especially when you look at them side by side. Both are handheld power tools with a pistol grip, and both of them take drill bits. Both have a power drilling mode, and they do it with hammering actions. Rotary hammers and hammer drills also come in both corded and cordless varieties, as well.
The difference, aside from the drilling range and the jobs that they are well suited for, is in how they apply the hammering force to the drill bit.
Hammer Drills: Hammer drills improve on the drilling and driving action of a drill bit by spinning two ridged discs against each other. These thick, cam-like disks are ridged just like a ratcheted wheel, and one of them rapidly rises up and down against the other disk.
These "hits" add a pounding force on the chuck which allow hammer drills to drive longer fasteners into harder materials much more easily than an ordinary drill can. This pounding action also lets hammer drills bore regular holes (smaller drill bits) quickly into masonry and concrete, as well.
Hammer drills, essentially, are drills improved by a hammering action.
Rotary Hammers: Rotary hammers, on the other hand, have something more powerful than two ridged cam disks. There’s a reason why they are much longer than the hammer drill – inside that shaft is a powered piston that compresses air to create the hammering effect.
With rotary hammers, most of the force comes from the piston, and the rotation is secondary. Rotary hammers do not spin the bit as quickly as the drill and the hammer drill but they hit it very, very hard.
In fact, most rotary drills come with a “hammer-only” mode that lets them operate with no bit rotation at all. They are, to put it simply, mini-jackhammers that happen to have a drilling action.
How Do I Pick The Best Rotary Hammer For My Needs?
Great rotary hammers are the ones that perform the best – blasting regular and large holes in masonry and concrete, day in and day out. The best rotary hammers, on the other hand, will deliver versatility on top of that, making them a handy tool that not only drills and fastens, but will also make them capable of demolition, surface prep, etc.
Generally, though, you want the most powerful rotary hammer for your budget. Bigger and more powerful hammers can stand up to everyday use even when drilling larger holes and will save you time and money in the long run.
Corded rotary hammers can range in price from $200 - $400. The smaller units tend to hover somewhere around that lower price point ($200) and the larger models can range in price from $300 - $400. These prices reflect name brands but I have seen cheaper rotary hammers for less than $200 but are less known brands.
Do take note, though, that the biggest and most powerful rotary hammers have streamlined features meant for heavy duty jobs. Regular rotary hammers will feature a drilling only mode, for example, that lets you use the rotary hammer without the impact driving action. The bigger models will typically come with hammer mode on all the time, as these are meant for the toughest jobs.
Rotary hammers are heavier and more expensive than ordinary drills. Think of them as a time-saving investment when it comes to getting a lot of quick drilling done, especially for those that need you to drill a lot of large holes in stone or concrete. The more use you have for a rotary hammer, the more money you should spend on a unit, it will make life a lot easier.
Features To Look For:
- Vibration control features work with rubber mounting and foam padding to ease the stress on your hands, which is very important when working with these types of tools all day long.
- Forward and reverse rotation modes let you back out of deep holes easier. They also allow you to insert or remove screws, bolts, and fasteners depending on the setting as well.
- Chisel function, (also called combination hammer function), stops the bit from rotating. This lets you use a variety of attachments that work best with the hammering action, such as chisel bits, spade bits, or blunt nose bits.
- Kickback control automatically shuts down the motor in case the bit gets bound up in the substrate you’re drilling, preventing the tool from wrenching itself free of your grip. This feature can be good or bad, depending on your preference.
- Variable speed control lets you adjust the rotation speed of your rotary hammer, usually in the form of a variable speed trigger control. These work well with a lock switch in some models that let you maintain the current rotation speed.
- Soft start, or enhanced tool control, slowly ramp up the RPM of the rotary hammer so you can control the speed better, which is crucial when you are working with or next to delicate materials.
- Built-in LED lighting lights up the target area, helping you see what you’re doing in darker areas.
- Dust extraction reduces the amount of dust and debris ejected by pulling most of it in a built-in dust bag or out to a vacuum cleaner attachment port. These are usually extra accessories that you have to buy separately.
- Brushless EC motors are more efficient, run cooler and makes it possible to have certain smart features like soft start or kickback control.
- Hammering switch lets you turn off the hammer function, letting you use the rotary hammer as an ordinary drill, if you need that functionality.
CORDED OR CORDLESS ROTARY HAMMERS?
Corded Rotary Hammers: Rotary hammers are powerful tools even among the other related members of the power tool family, and they can use up a lot of juice. Having a corded rotary hammer lets you keep on drilling without having to wait for a recharge, and quality units will usually have a good length of cord for you to work with – 12' or more are fairly standard.
Corded models are also a little bit cheaper than the cordless models if you include the price of batteries, the tool and a charger. If you already have batteries and a charger and just need the tool, it is much more affordable.
Cordless Rotary Hammers: Cordless rotary hammers, on the other hand, are simply more handy to handle, with no cord to get in the way. They are perfect if you are working up on ladders or on scaffolding, and the better batteries that come with good brands can hold quite a good amount of charge – usually enough for more than 200 holes in concrete for a good 6 Ampere-hour (Ah) battery.
Cordless Rotary Hammer Features To Look For:
- Quick chargers will save you time waiting for batteries to charge.
- Chuck sizes can vary between cordless models from 1" to 1 3/4" so keep this in mind when choosing a model.
- Keep an eye out for accessories that come with some of the cordless models like a dust collection system.
- Brushless EC motors are simply more efficient, letting you do more for the same charge.
The Many Different Rotary Hammer Attachments:
Rotary hammers, especially those with the chisel function, can use special attachments that make them suitable for tasks other than drilling holes in concrete.
- Tile remover attachments are flat, chisel-like add-ons that can quickly strip a concrete wall clear of tiles and compound. Very useful for remodeling jobs.
- Bull point chisels turn your rotary hammer into a mini-jackhammer, for putting in rough starting holes in concrete and masonry
- Scaling chisels help you with surface prep by chiseling off hardened concrete, weld splatter, rust and paint lumps.
- Clay spades are used to break up hard soil and substrate.
- Cold chisel attachments are mostly for breaking up concrete for demo jobs.
- Rebar bits are specially hardened bits that can drill through rebar and mesh wire where standard carbide bits would likely break.
A Word On The Different Bits (Shank Explanation)
You will need to keep in mind what type of bits your rotary hammer will accept. The two most common types of bits are the SDS Max and SDS+ bits (includes SDS bits). There is a helpful video that explains the three different bit types that I think is worth sharing...
How Do I Compare Rotary Hammers?
Chances are, you are buying a rotary hammer with a certain set of jobs in mind. To help you choose the right tool for the right job, consider the sizes of the holes you need to drill. The bigger the holes you need to drill, the more powerful unit you need to get.
The other thing to consider is how much you will be using the rotary hammer. If you only plan on using it once or once in a great while, then a smaller and cheaper model will suffice ($200 or less). If you have a lot of work to do with it, then you will want to consider a larger unit ($300 and up) will be a much better choice.
POWER RATING
The power of the main motor is measured in Watts (W). Oftentimes, this is the rated input power figure – the output power of a rotary hammer is affected by too many factors like gearing and attachments to have a consistent rating.
Corded rotary hammers are also rated in terms of Amps (A), while cordless rotary hammers have voltage (V) ratings. For battery-operated models, running time can be estimated from the battery capacity rating, usually given in Ampere-hours (Ah).
IMPACT AND SPEED
Like most tools with impact operation modes, rotary hammers have impact energy ratings. Impact energy is given in Joules (J) – the higher the figure, the harder the piston can slam into the chuck.
Rated speed is usually given in rotations per minute (RPM), and compared to drills and hammer drills, rotary hammers usually spin in the sub-1,000 RPM or slower. Slower RPM speeds are better for these types of tools.
What they lack in RPM, they make up in sheer impact power, however, and these hits come in hard and fast. Hammering speed is given as an impact rate in terms of beats per minute (bpm), and typical rotary hammers can have impact rates up to 4,000 bpm or more.
DRILLING RANGE
This is one of the most important considerations you will need to look at when buying a rotary hammer, and manufacturers will usually give out detailed estimates of the drilling range of their tools. Drilling ranges are usually specified in millimeters (mm) for metric scales, or inches (in.) for imperial specifications.
Maximum drilling diameters are usually provided for masonry, wood, and metal materials and will usually have a maximum diameter type of spec associated with the tool.
