If you were a professional contractor who used various types of drills on a daily basis throughout the course of your job, you would probably already know what type of drill you need for a specific job. But, what about the person who does not work with drills every day. This person probably knows that a certain job or task requires the use of a drill, but may not be certain about what type of drill is needed. Choosing the right drill can be a daunting task and it's really no surprise with all the types of drills to choose from. You have:
basic drills
VSR drills
drill/drivers
hammer drills
impact drivers/wrenches
rotary hammer drills
right angle drills
spade handle drills
Maybe you have already been looking at drills and have other questions such as:
What does VSR mean?
What is the difference between SDS and spline drive?
How does chuck size matter?
What is the difference between keyed and keyless chucks?
What is a hex driver?
Should I go with a cordless or corded drill?
What type of cordless battery is best?
What is the clutch used for?
Many years ago, when the first hand held power drills came around, there were not many choices outside of brand names when it came to selecting a power drill. Basically, the drills were all corded, all had keyed chucks, and rotated in only one direction and at one speed. So, the choice was not too difficult. Just pick a brand you like.
Things certainly have changed over the years. There are enough options available today to make a person's head spin. There are even more variations and innovations in the works as I write this. While the scope of this guide will not be able to cover every type of power drill in existence, we are going to try to cover most of the bases. My goal in writing this article is to help those who might be having difficulty deciding which type of drill they need, so let's get started.
The basic corded drill
This is the most basic of hand held power drills. It is a simple electric drill with one speed and one direction. It is mainly good for drilling holes in wood, metal, plastic, and soft metals. It is not the ideal choice of drill to use for applications such as driving screws. Since the speed is not variable and the drill only operates at a higher RPM, you would likely either strip the screw head or snap the head off the screw if you tried. You will not likely find many of these around today as their uses are rather limited.
The VSR drill
VSR stands for "variable speed reversible". These drills come in both corded and cordless versions as will most all the drills we discuss from here on out. The drill speed is varied by the amount of pressure applied to the trigger. The farther the trigger is pulled, the higher the RPM will be. There is also a switch, usually near the trigger which reverses the operation of the drill. As you can imagine, these have distinct advantages over the basic corded drill. In addition to being able to perform all the functions of the basic corded drill, they also have a better suited although still limited ability to drive screws, and small lag bolts. Since the speed is variable, you have the ability to drill into harder material without overheating the bit.
One disadvantage to this type of drill is that trying to maintain a certain RPM with the trigger can be very tricky. It takes a certain knack and some getting used to in order to be able to drive screws consistently without stripping the heads, driving the screw too deep, or snapping off the screw head. The reversible feature allows you to remove screws, drive reverse threaded screws, and back out of stock when your drill bit gets stuck or jammed.
The VSR drill/driver
The VSR drill/driver has all the capabilities of a standard VSR drill with the added bonus of a lower rpm/higher torque setting. Another feature generally found on these drills is an adjustable clutch. These are probably the most common types of everyday use cordless drills you will find on the market today. The big advantage with the low rpm/high torque setting is that now you can drive screws and lag bolts at the low rpm needed without having to try to hold the trigger in a certain position. The adjustable clutch will keep you from driving the screw to deep, stripping the screw head, or breaking off the screw head. The clutch will also prevent reaction torque which happens when a bit jams or a screw bottoms out and the drill tries to twist in the opposite direction. In addition you also get higher torque at the low rpm setting that you miss out on when using a standard VSR drill and higher torque means more screw driving power. These drills generally have a slide switch that you use to switch between the 2 settings. In the high RPM setting, the drill functions exactly like a standard VSR drill. In the low rpm/high torque setting, the drill becomes an effective driver for driving screws and small lag bolts. Some of these drills may have a 3rd intermediate setting that compromises between torque and speed allowing you to better match the speed/torque setting to the application.
The VSR hammer drill/driver
Do you need to drill into concrete, stone, or masonry? If, so, then you would want to consider a hammer drill. This type of drill uses a hammer or pounding action as the drill bit rotates. The pounding action of the bit is what enables these drills to bite into the concrete, stone, or masonry. If you were to try to use a non-hammer type drill, you would have a hard time penetrating the hardened concrete, stone, or masonry and would likely overheat the bit or the bit would become jammed in the material. When drilling into concrete, stone, or masonry you will also want to be sure and use a masonry bit. A masonry bit is specially designed for drilling into these materials. Depending on the material, the drill and the bit used, you can generally expect to be able to effectively drill holes in concrete, stone, or masonry up to around 1/2" in diameter. VSR hammer drill/drivers have all the capabilities of a VSR drill/driver in addition to functioning as a hammer drill at the flip of a switch. Due to their versatility, hammer drill/drivers have become a popular choice among both professional contractors and do-it-yourselfers. Some practical uses would be, drilling holes for inserting concrete anchors or TapCon screws for attaching fixtures such as hand railing or light posts to concrete surfaces or attaching fixtures to concrete, block, stone, or brick walls. One of the most highly and professionally rated hammer drill/drivers on the market today is the DeWalt DC925KA.
Rotary Hammer Drills
Think of a rotary hammer drill as a larger, more powerful version of a hammer drill with an added bonus. It also works like a small jack hammer. These drills are dedicated to the purpose of drilling and chipping into concrete, stone and masonry. They are generally not intended for drilling into wood or other similar materials. Rotary hammer drills use a special bit designed not to slip in the chuck. The most common types are the SDS and spline drive. The type of bit you use will depend on the drill. SDS bits come in several different sizes, so you will need to get the size that matches your drill. If you want to drill many larger diameter holes in concrete or stone, then this is the type of dill you need.
As mentioned, this drill also functions like a small jack hammer. By flipping a switch you can turn off the rotary action, then insert a chisel bit and you're ready to go. While rotary hammer drills aren't going to compete with a full sized jack hammer, they are very useful for many smaller jobs such as removing ceramic and stone tile, removing bricks and blocks from existing wall or floor structures, chipping away unwanted or spilled mortar, chipping the rough edges from concrete, and removing excess concrete from concrete forms or other surfaces.
Traditionally, rotary hammer drills were all of the corded variety since cordless batteries were not able to supply the power needed to operate a rotary hammer drill. However, all that is changing with advancements in lithium-ion batteries and power tool design technology. The popularity of cordless rotary hammer drills is growing rapidly. Some cordless rotary hammer drills rival, and may even surpass the performance of their corded counterparts. One such example is the Bosch 11536VSR which in an HGTVpro power tool review was found to drill 1/2" holes in concrete faster than the tool's corded counterpart.
Impact Drivers/Wrenches
Impact drivers are quickly becoming a hot item among contractors and do-it-yourselfers and with all the added benefits of an impact driver, it's no wonder. If you drive a lot of long screws, lag bolts, or have a lot of nuts and bolts you want to assemble quickly and easily, then an impact driver is for you.
The impact driver functions as a standard VSR drill until the time when extra torque is needed. That's when the impact action kicks in. Don't confuse this with the hammer action of a hammer drill. The difference is that a hammer drill "hammers" on the bit in a lateral direction along the length of the bit as it rotates where an impact driver impacts the chuck of the drill in a rotational direction. The result is a huge increase in torque. The impact action also causes the screw bit to grab the screw resulting in less slippage, reducing the possibility of stripping the screw head. As an added bonus the amount of force the operator needs to apply to the drill in order to keep the screw bit from slipping is significantly reduced resulting in less user fatigue.
Impact drivers have a quick change bit holder designed for accepting hex shank bits which are now common among screw bits and many other drill bits and socket driver bits. This style bit holder really makes changing between bits a snap. This bit holder is the main difference between an impact driver and impact wrench. An impact wrench has a square drive for accepting either 3/8" or 1/2" drive sockets depending on the model of impact wrench.
Impact drivers and wrenches also have a size advantage delivering as much as 4 times as much torque as a comparable size VSR drill. This means that a smaller size tool can be used for a particular job which further reduces user fatigue, especially when working overhead. The small size also gives you the ability to work in tighter spaces and if the impact driver uses lithium-ion technology, then the tool weight is even further reduced.
There is one particular impact driver that stands out. In a tool test by Tools of the Trade Magazine, out of 9 top of the line cordless impact drivers, the Milwaukee 9081-22 was able to outrun the group when pushed to the max. This tool sent 48 4" long Timberlock screws into the stock before a noticeable battery slowdown was observed. Timberlock screws are a long screw with a hex head. They are commonly used in outdoor applications such as landscaping, fence and deck building because they require no pre-drilling. Just think of the time you could save when armed with an impact driver and screws that require no pre-drilling.
Right Angle Drills
Right angle drills, as the name implies, have the chuck positioned at a right angle to the body of the drill. Right angle drills are able to drill in tight spaces where other drills just won't reach such as in between two closely positioned wall studs which makes these drills particularly useful for plumbers and electricians.
These drills come in both corded and cordless varieties as well as a wide range of sizes. The smaller size right angle drills are suitable for small to medium jobs in pine and other soft material. The heavy duty models can handle much larger jobs in harder material such as thick oak. One thing you should be aware of when using the more powerful heavy duty models is reaction torque. Due to the design of right angle drills, if the bit should get stuck, the entire drill body will rotate around the chuck potentially causing injury. It's generally a good idea to brace the drill against a floor, wall, or stud. Some models have a built in torque limiter or clutch to help prevent this occurrence. One such model which has a built in torque limiter is the Makita DA4031 [http://www.thetoolspot.us/Products/Makita/Makita-DA4031/MAKITA-DA4031.html]. This heavy-duty right angle drill was also the overall winner in a Tools of the Trade test of several top of the line right angle drills.
Spade Handle Drills
When spade handle drills are mentioned, one might likely think of mixing drywall compound. The mixing of drywall compound or similar substances is one of the most commonly used applications of spade handle drills. These drills are designed with a low rpm, high torque setting that is well suited for mixing drywall mud. Special drywall mixer attachments can be inserted into the chuck for this purpose.
While these drills are very suitable for mixing drywall mud and other similar substances which require mixing, this is certainly not the only use for this type of drill. The aggressive torque these drills produce make them ideal for boring large holes in wood and other materials using spade bits, auger bits or hole saws up to as large as 5" in diameter.
Many of these drills have a rocker or similar type of switch for rapid switching between forward and reverse which aids in backing out jammed bits as well as mixing drywall mud. In addition, these drills generally have an auxiliary side handle as well as a spade handle to aid in tool control.
Questions and answers pertaining to power drills.
What does VSR mean?
VSR stands for variable speed reversible. Drills with this feature are able to operate in both forward and reverse rotation and at variable speeds. Most likely the drill will have a switch or button for switching the rotation from forward to reverse. Generally the speed varies in relation to to how far the trigger is pulled.
What is the difference between SDS and spline drive?
SDS and spline drive refer to two types of bit technology used in rotary hammer drills. There is really no difference in the performance of the two types, so the one you choose will simply be a matter of which type your particular rotary hammer drill requires. There are different sizes of SDS bits which include SDS, SDS+, and SDSmax. Smaller rotary hammer drills will use SDS or SDS+ bits where the larger rotary hammer drills will use SDSmax or spline drive bits. As the name implies, spline drive bits have a splined shaft, while SDS bits have concave recesses in the shaft.
Why does chuck size matter?
Chuck size basically determines what size drill bit you can use based on the size of the drill bit shank. With the exception of rotary hammer drills and impact drivers/wrenches which use a special type of chuck, most typical hand held drills come with either a 3/8" or 1/2" chuck. Most of your smaller drills will use a 3/8" chuck while the heavy-duty models typically use a 1/2" chuck. You cannot put a drill bit with a 1/2" shank in a 3/8" chuck, but you can put a bit with a 3/8" shank in a 1/2" chuck.
What is the difference between keyed and keyless chucks?
Years ago, all hand held drills used keyed chucks. In order to tighten the chuck down on the drill bit, you would use a small tool called a chuck key. Most 3/8" chucks and many 1/2" chucks today are now of the keyless variety. Keyless chucks, as the name implies, do not use a chuck key. Instead the chuck is designed so that a person can easily tighten the chuck down on the bit by hand. While keyless chucks are faster and easier to use, they cannot clamp down onto the bit as tight and therefore do not have the same holding power as a keyed chuck. This lack of holding power can potentially cause round shank bits to slip in the chuck. This is why you will still find many heavy-duty high torque drills using keyed chucks.
What is a hex driver?
A hex driver is just another name for an impact driver. Hex refers to the type of bit holder the drill uses. These drills use a hex shank bit designed not to slip in the holder. This type of bit holder also makes changing bits a snap. Impact wrenches, on the other hand use a square drive for accepting either 3/8" or 1/2" drive sockets.
Should I go with a cordless or corded drill?
This can be a difficult decision for some. The industry trend is ever going more and more towards cordless technology. The very first cordless drills on the market left much to be desired in both power and run time. Over the years cordless technology improved to the point where many cordless tools now compete with and even in many cases out perform their corded counterparts. With power and performance becoming near equal, the choice basically comes down to price. Are you willing to save some money and deal with the inconveniences of dragging power cords around, or would you rather spend a little more and have complete freedom of movement? The choice is yours.
What type of cordless battery is best?
The power tool industry is currently trending toward lithium-ion battery technology. With all the benefits of lithium-ion it is easy to see why. If you compare lithium-ion batteries to nickel cadmium batteries, lithium-ion charges faster, runs longer, maintains longer constant power output, weighs less and stores a charge longer. The disadvantage is that Lithium-ion costs more. However, the difference in price may not outweigh the advantages you get in performance and charge holding time.
What is the clutch used for?
Most drill/drivers and hammer drills have an adjustable clutch. The clutch is typically used when driving screws, nuts, or lag bolts. The clutch is designed so that once a certain required amount of torque is reached, the clutch will engage and cause the rotation of the chuck to slip and stop rotating. There are several reasons for this. One, you won't strip the screw head when the bit keeps turning. Two, you won't drive the screw too deep. Three, reaction torque when the screw or nut bottoms out won't twist your wrist. Many drills produce enough reaction torque to cause bodily harm if the clutch is not used. Many heavy-duty drills capable of producing high amounts of reaction torque have either a non-adjustable built in clutch or a built in torque limiter. An finally, the clutch protects the drill motor from damage.
