A rotary hammer can’t get any work done without one of the many drill bits and tool attachments available on the market. It can get confusing as you try to figure out which bits work with the rotary hammer that you have, and then there’s the fact that you have to consider if it will be the best bit for the job.
It was even more confusing in the old days of proprietary rotary hammer shank standards – nowadays, however, things have become more or less standardized along three or so of the most popular types.
Between SDS Plus, SDS Max and Spline, you will have an endless pick of various drill bits, core bits, chisels and spades that lets your tool drill, dig, chisel and hammer.
Rotary Hammer Bit Sizes
When it comes to rotary hammers, your choice nowadays basically boils down to two basic sizes. You either have a smaller SDS Plus compatible tool, or you have a heftier SDS Max or Spline machine.
Contractors on the go will usually have a smaller SDS Plus rotary hammer in their toolkit that lets them equip drill holes up to 1 and 1/8 inch wide, or use core bits up to 4 inches in diameter. The bits for these tools have shanks with a diameter of 10 mm, just enough for shorter bits and smaller attachments.
On the job site, though, the SDS Max or Spline rotary hammer is a more reliable option for drilling holes up to two inches wide. They can also use carbide core bits up to six inches in diameter – more importantly, they can equip the extra-long drill bits over a foot long.
1. SDS Rotary Hammer Drill Bits
SDS rotary hammers are designed for drilling into concrete and masonry, and SDS itself is an older standard designed to be used for hammering applications. The SDS in the name stands for “Steck, Dreh, Sitz” or Insert, Twist, Stay in the original German, and has taken over other standards due to the simple convenience of being able to load a drill bit with just one hand, without the use of tools. In international markets, Bosch also calls it “Special Direct System”.
SDS rotary hammer bits have a shank with a diameter of 10 mm, which is held rather loosely by the spring-loaded chuck. This lets the rotary hammer safely deliver more impact to the flat end compared to bits that are held rigidly in place like in the other tools.
2. SDS Plus Rotary Hammer Drill Bits
The SDS Plus standard is an improvement over the older SDS system, offering more reliable connection with the tool while also being completely interchangeable with SDS. That means if you already have a collection of older SDS bits, you can use them in your SDS Plus tool with no problems. SDS Plus bits may also be labeled as TE-C bits, and they are now by far the most common in the market these days.
SDS Plus rotary hammer bits have four indentations, two of them open ended. Just like SDS bits, these also have a shank diameter of 10mm.
3. SDS Max Rotary Hammer Drill Bits
SDS Max first started as an alternative to the older Spline chuck systems as the heavy-duty option for rotary hammers. SDS Max retains the easy bit changing features of the SDS system, while also offering higher torque tolerance. SDS Max bits are on the larger side of things, and in this range, you will find drill bits up to 2 inches in diameter becoming available.
SDS Max shanks have five indentations, three of them open ended. The shanks themselves have a diameter of 18 mm, which offers plenty of supporting material for the biggest bits you can ever find for your rotary tool.
4. Spline Rotary Hammer Drill Bits
Spline rotary hammer drill bits is an older standard, true, but it still offers a few benefits over the more modern SDS Max standard. Simply put, Spline chuck systems can handle a higher amount of drilling torque, and will hold up even in the heaviest of drilling workloads.
Unlike SDS systems that use a spring-loaded mechanism, Spline shanks have 12 precisely ground teeth or splines that fit into the chuck with no play, and is afterwards secured by a retaining pin.
Just like SDS Max bits, Spline bits are available for drilling holes up to 2 inches wide. Spline shanks also have a slightly larger diameter of 19mm, and they are not compatible with SDS Max tools. Fortunately, adapter bits are now available that will let you use Spline bits on an SDS Max rotary hammer, or the other way around.
5. Extra Long Rotary Hammer Drill Bits
Rotary hammers are designed to drill holes into concrete, and sometimes, you need to drill all the way to the other side of that concrete wall. Extra long rotary hammer drill bits are available just for that purpose – even the smaller SDS Plus standard have bits 1.5 meters long.
These one-and-a-half meter long bits are designed to dig deep into concrete, and even past that into brick and stone.
These extra long bits are useful for installing deep anchor fixings in concrete beds, granite, and solid bedrock.
6. Rotary Hammer Concrete Drill Bits
Rotary hammers are specifically designed to drill through concrete, stonework, and masonry, and it’s no surprise that you have a wide variety of concrete drill bits to let you drill just about any depth or diameter you may need. Most concrete drill bits are carbide-tipped at the end for longer life and better cutting performance.
7. Rotary Hammer Wood Drill Bits
Rotary hammers may not be the ideal choice for drilling through wood, with the slower RPM that they put out. Nonetheless, manufacturers do make drill bits designed for wood to be used with hammers. Many of them have a brad point to provide clean holes through wood, even if you use a “hammer and drill” mode with them. That said, these bits are designed for “drill only” mode.
8. Rotary Hammer Rebar Cutter Bits
Drilling through steel-reinforced concrete can spell the end for many concrete drill bits, with their ends getting blunted if they are forced to go through rebar. For drilling through rebar, a rebar cutter bit is the smarter choice. Slap one in your rotary hammer, switch to rotation only mode, and cut out the rebar in the way.
9. Rotary Hammer Chisel Bits
Rotary hammers often feature a “hammer only” mode, which makes them extra useful for a lot of chiseling tasks. A lot of chisel type tool attachments have been developed for specific tasks, more than you might expect.
You can have pointed chisels for chipping and demolition, or wide flat chisels for scaling, tile removal, and surface smoothing. You can also put on a flex chisel on your rotary hammer to scrape off linoleum tiles and carpets, too.
There are also bushing and slotting tools available for rotary hammers that let you roughen up surfaces and gouge out grout in brick and stone. Check that you have your rotary hammer set to “hammer only” mode to properly use a chisel bit.
10. Rotary Hammer Spade Bits
Rotary hammer spade bits are useful for demolition or digging, combined with a “hammer only” setting on your tool. A clay spade shove bit can break up hard clay, and is a handy attachment to have for all around soil removal and digging. Some spade bits also come curved for trenching jobs as well.
11. Rotary Hammer Core Drill Bits
For gouging out perfectly round holes in concrete and masonry, you will need a core drill bit on your rotary hammer. If you’re already familiar with a hole saw, the same principle applies here – a pilot bit helps center the core drill on the target area, while the rest of the bit digs into the perimeter of the hole.
Regular core wall bits can cut out holes up to 4 inches wide, while “thin wall” core wall bits made for larger SDS Max or Spline rotary hammers can cut out round holes up to 6 inches wide.
12. Rotary Hammer Auger Bits
Rotary hammers can take a lot of work out of digging holes in the ground, thanks to auger bits the lets you dig deep, uniform holes into soil or even clay. Helical auger bits can also be used for cultivating soil and mixing tasks, as well. Toothed auger bits with tubular core bit designs can dig even deeper, even into solid frozen ground.
13. Rotary Hammer Rod Adapter Bits
Rod adapter bits for rotary hammers give you an easy and efficient way of driving earth rods into the ground. One end goes into your tool, and you can fit an earth rod on the other end.
Place the earth rod over the target patch of ground you need to drive it in, and let the tool do most of the work. They are very useful tools for installing 8-foot long copper ground rods, especially if you’re a professional that needs to install several of them at a time.
