If you are looking to work with concrete or masonry – and need to drill holes – chances are you looked at getting a regular hammer drill or heavier duty rotary hammers like the Hilti TE 7-C. In the latter case, rather than regular concrete drill bits, you will generally need to get SDS drill bits.
In this article, I take a look at what makes the SDS system unique, at what the differences between regular SDS, SDS Plus, and SDS Max are, as well as at some of the most commonly asked questions about the topic.
SDS Drills: What Are They and How Do They Work?
An SDS drill is a more capable and powerful alternative to a standard hammer or rotary drill. It can easily drill through brickwork, concrete, steel, and tougher materials. Using two different types of motion, it maximizes efficiency and allows the user to apply much more force to the materials at hand.
SDS drills have an internal hammer mechanism in their specialized chuck. Looking at an SDS bit helps you to understand why the chuck has to be equally special. There are indentations along the shaft of the bit that fit between ball bearings in the chuck.
The hammer is like a piston – the SDS bit gets shot forward and backward which gives a more accurate and precise action compared to a standard hammer drill. That’s because with standard hammer drills, it’s their chucks that move back and forth, not the bits themselves.
By isolating motion in the bit, it allows for less chatter, more efficiency, and much higher accuracy.
An SDS drill has a switch allowing for the hammer option to be turned off and to perform like a standard rotary drill. That way, it can be used with softer materials.
What Are SDS Drill Bits?
An SDS drill bit is, as its name suggests, a bit designed to be used with an SDS rotary hammer drill. The dual action of rotation coupled with proper hammering makes chiseling and drilling through hard materials much easier than with a standard drill bit. An SDS bit is quite different than a standard bit and is composed of five parts.
The shank overall works the same way as a standard drill bit. The big difference, though, is that an SDS bit shank has four grooves on it that fit into the drill’s collar. The grooves guide the bit to allow it to rotate, as well as ensuring the bit doesn’t fall out of the chuck. Additionally, the grooves allow the bit to slide within the chuck which means better energy while hammering, and better torque while drilling.
The land of the bit is the raised portion of the spiral Next is the flute which performs exactly the same as it does with a standard bit. It removes dust and debris while the drill is drilling or hammering a workpiece.
The head of an SDS drill bit works to break up the concrete similar to the head of a standard hammer drill bit. Lastly, a bit’s carbide tip works with the head to break up the concrete. It’s generally brazed which makes the head of the bit much stronger than it would otherwise be.
SDS vs. SDS Plus vs. SDS Max: What Are the Differences?
All three of the variants – SDS, SDS Plus, and SDS Max – work on the same principle and are based on the same concept. Their composition is the same, but there are nuances between each that make them unique.
Moving along the list, you go from lightest-duty to heaviest-duty. SDS and SDS Plus bits are interchangeable since they’re both 10mm diameter and the latter is just a modernized version of the former. SDSMax bits are, at 18mm diameter, larger and thus do not work with SDS and SDS Plus drills.
With SDS being outdated and replaced by SDS Plus, the latter is the most commonly used type of the format on the market. It has more indentations on the shaft which results in a more efficient and accurate use. SDS Plus bits are practical, offer good performance, and are priced decently. They are ideal for most masonry and concrete work uses.
As mentioned earlier, SDS Max is a heavy-duty alternative to SDS Plus. It is most commonly used in the most demanding masonry and concrete work applications. Since both the bits and the drills are more expensive compared to the standard SDS Plus, you should avoid SDS Max unless you absolutely need it.
If you do need it, though, make sure to check my list of recommended SDS Max drills.
A 7.0 amp rotary hammer accepting SDS Plus bits.
A corded demolition hammer accepting SDS Max bits.
SDS Drill Bits: Other FAQs
The above should give you a good overview of SDS bits. However, I’m sure you still have some questions about the system.
That’s why below, I compiled a list of some of the most commonly asked questions and their answers.
Can SDS drill bits be used in a non-SDS chuck?
With the specialized drill bit that is an SDS, you need a specialized chuck to accept the bit. Standard, or in other words non-SDS, chucks will not accept SDS drill bits.
Even if you force the SDS bit into a regular rotary or hammer drill, the bit could damage your drill, it could come loose, and your project will not go smoothly.
Can I use regular drill bits in an SDS drill?
No, regular bits cannot be used in an SDS drill. The quick answer is that the stock chuck cannot accommodate a standard drill bit.
That said, there are ways to “hack” the SDS drill chuck with an adapter to allow it to accept regular bits. If you do that, though, keep in mind that you cannot use a regular drill bit in hammer mode – only use it in rotary mode.
Can I use an SDS Plus bit in an SDS drill?
Yes, SDS and SDS Plus drill bits are interchangeable. The difference is that SDS Plus bits have extra indentations. Regardless of this, an SDS Plus bit can be used in an SDS drill and vice-versa.
How should I insert SDS bits into a drill?
As you might expect, this unique drill bit type does not insert the same way as a standard drill bit. The instructions are typically provided when you buy an SDS drill bit, but they go as follows: insert the bit with a twisting motion until it latches firmly. Push until the bit clicks and ensure that you cannot pull out the bit by hand.
For newer drills, you may have to pull back the locking sleeve on your drill.
In either case, you might want to read my guide on how to change a drill bit.
What does SDS stand for?
SDS generally stands for “Slotted Drive System,” a meaning adopted by the industry after the system was developed. There are other less common meanings to the acronym, though.
The original German interpretation of this acronym was “Steck-Dreh-Sitz” which translates to “Insert-Twist-Stay,” quite a literal name for the bit. Other interpretations of SDS include “Slotted Drive Shaft” and “Special Direct System.”
Though each interpretation of the acronym is a little different, they all explain the system well.
Do SDS bits work differently compared to standard bits?
Yes, SDS drill bits operate differently than your typical drill bit.
Standard drill bits in rotary mode spin due to the chuck spinning. In hammer mode, the chuck oscillates forward and backward to achieve the hammering motion. SDS drill bits are different in that the bit itself is at the heart of the motion. The bit hammers back and forth in the hammer mode. In the rotary mode, it’s the bit itself that spins rather than the chuck.
How much should I lean on an SDS drill while drilling?
Let the engineering behind the SDS drill and bit do all of the hard work for you. This tool will cut easily into concrete, you just have to focus on holding the drill level and making sure you’re applying even pressure the whole time
Do I need to do maintenance on my SDS hammer drill?
It is suggested that you lubricate the connections before using your bit. This can be done by putting some lube at the base of the bit before sliding the shank into the chuck. A dollop along the grooves in the shaft will allow the assembly to fit together nicely and prevent damage or internal abrasion over time.
Do I need to check anything before using an SDS bit?
It is always good practice to have a once-over on your tool before starting a job.
Check the carbide tip and make sure there are no nicks or notches. Check the connection and ensure there’s no excessive wear on the assembly. If your tool or chuck is worn, your bit might get stuck in the chuck or fall out while operating.
The main thing that distinguishes SDS drill bits from regular ones is that they are designed to move by themselves. In other words, the SDS chuck stays stationary – unlike a regular hammer drill one which spins and hammers.
That allows the drilling action to not only be more powerful but also more precise.
While there are three types of SDS bits – regular ones, SDS Plus ones, and SDS Max ones – in most cases, you will only need to know the second. The first is outdated by this point, and the last is only used for the heaviest duty applications.