SDS Plus vs. SDS Max: Which Bits Fit Which Rotary Hammer
SDS Plus and SDS Max bits don't swap: one has a 10 mm shank, the other 18 mm. Which bits fit an SDS Plus rotary hammer, how to run regular twist bits, and how a rotary hammer differs from a hammer drill.
In this guide
SDS Plus and SDS Max are two different bit shanks, and a bit only fits a tool built for its own shank. Bosch gives SDS Plus a 10 mm shank and SDS Max an 18 mm shank, and says plainly that the two systems are not interchangeable. SDS Plus covers lighter and medium-duty work such as anchor holes in masonry. SDS Max is for bigger holes and heavier chiseling. A hammer drill is a third case: it has an ordinary chuck and takes neither.
SDS Plus and SDS Max side by side
| Spec | SDS Plus | SDS Max |
|---|---|---|
| Shank diameter | 10 mm | 18 mm |
| Hilti's name | TE-C | TE-Y |
| Bit capacity on Bosch hammers | 3/4 in. to 1-1/4 in., by model | 1-9/16 in. to 2 in., by model |
| Typical jobs | Drilling masonry, setting anchors, light chiseling | Oversized anchor holes, rebar, breaking through slabs and walls |
| Tool size | Lighter and more compact | Built for heavier workloads, greater impact energy |
The capacities and jobs come from Bosch's SDS-plus and SDS-max hammer pages. A given tool can be rated lower than the top of its range: Milwaukee rates the compact M18 2612-20 for carbide percussion bits up to 5/8 in. in concrete.
An SDS Max bit won't go in an SDS Plus tool
The SDS Max shank is 18 mm across and the SDS Plus bit holder is made for a 10 mm shank, so the bigger bit won't go in. Bosch's answer on mixing them is "No": bits must match the tool's chuck system. We found no maker adapter that puts an SDS Max bit into an SDS Plus tool.
The other direction does exist. Hilti sells the Spindle TE-Y-BFH, an adapter for the TE-Y (SDS Max) chuck that lets you run drill bits, chisels and other accessories with the TE-C (SDS Plus) connection end. Without an adapter like that, an SDS Plus bit doesn't belong in an SDS Max hammer either.
SDS and SDS Plus shanks
Bits sold as plain "SDS" and as "SDS Plus" both fit an SDS Plus tool, going by Milwaukee's manual for the 2612-20. Its bit holder is SDS Plus, and the manual says: "Only use accessories with SDS or SDS Plus shanks." SDS Max is the one that differs, with its larger 18 mm shank.
The 2612-20 manual gives these steps for fitting a bit:
- Wipe the shank clean and grease it lightly.
- Push the bit into the nose and turn it slowly until it lines up with the locking mechanism.
- Push it in until it locks.
- Check it: the bit should slide back and forth about 1/4 in.
- To take it out, pull the release collar toward the back of the tool.
Tip That 1/4 in. of play is normal on an SDS bit. Bosch also recommends grease on SDS Plus shanks for smoother insertion and removal.
Regular drill bits in an SDS Plus rotary hammer
Round-shank twist bits don't lock into an SDS Plus holder on their own. Milwaukee's answer is the 48-66-1370 SDS/Chuck Adapter Kit: a 1/2 in. chuck, an SDS to 1/2-20 thread adapter, a chuck screw and a chuck key. With it, the 2612-20 runs straight-shank twist bits.
The manual puts the adapter under drilling wood, composition materials and plastic, with wood augers or twist bits. Its steel and wood capacities are listed under drill only: 3/8 in. in steel and 1/2 in. in wood. Drill only is the mode selector position with the twist drill symbol. Hilti lists the same use for its TE 2-S: occasional drilling in steel, wood and plastics with an optional chuck adapter.
Warning Milwaukee says to take the battery pack off before you change or remove accessories, and to use the side handle every time you run the 2612-20.
Rotary hammer vs. hammer drill
A hammer drill turns the bit and, in hammer mode, also drives it forward, which makes masonry easier to drill (DEWALT's description). A rotary hammer gets its blows from a piston. Bosch says this piston-driven action exceeds a standard hammer drill. The bit system differs too: rotary hammers take SDS bits, hammer drills take ordinary bits in a chuck.
Milwaukee's two M18 tools show the trade-off:
| Spec | 2612-20 rotary hammer | 2904-20 hammer drill |
|---|---|---|
| Bit holder | SDS Plus | 1/2 in. keyless chuck |
| Speed | 0–1,300 RPM | 0–500 and 0–2,100 RPM |
| Blows per minute | 0–7,000 | 0–33,000 (high speed) |
| Masonry capacity | 5/8 in. carbide percussion bit | 5/8 in. |
| Steel / wood | 3/8 in. / 1/2 in. (drill only) | 1/2 in. / up to 3-1/2 in. hole saw |
| Driving screws | Not listed | Yes, clutch with torque settings |
Both manuals rate 5/8 in. in masonry. Blows per minute is a count of blows; neither manual gives the energy of each blow. The 2612-20 manual lists two modes, drilling and rotary hammering, and no chisel-only mode.
Picking one
- Anchor holes in concrete with SDS Plus bits, on an M18 battery you already own: the Milwaukee 2612-20 SDS Plus rotary hammer (tool only).
- Wood, metal and screws first, with occasional masonry holes in hammer mode: the Milwaukee 3699-22 kit with the 2904-20 hammer drill, a SURGE hydraulic driver, two batteries and a charger.
We don't carry an SDS Max hammer right now. More tools are in Power & Air Tools.
FAQ
Can I use an SDS Max bit in an SDS Plus drill?
No. The SDS Max shank is 18 mm and the SDS Plus holder takes a 10 mm shank, and Bosch says the two systems are not interchangeable. The maker adapters we found, such as Hilti's, go the other way: they let an SDS Max hammer run SDS Plus bits.
Are SDS Max and SDS Plus the same size?
No. Bosch lists a 10 mm shank for SDS Plus and 18 mm for SDS Max. Bosch's SDS Plus hammers take bits from 3/4 in. to 1-1/4 in., its SDS Max hammers from 1-9/16 in. to 2 in., depending on the model.
Can you use regular drill bits in an SDS Plus drill?
Yes, with a chuck adapter. Milwaukee's 48-66-1370 kit fits a 1/2 in. chuck to an SDS Plus rotary hammer so it can run straight-shank twist bits. Milwaukee's 2612-20 manual lists the adapter for drilling wood, composition materials and plastic.
Is SDS the same as SDS Plus?
For fit, an SDS Plus tool takes both. Milwaukee's 2612-20 manual says to use accessories with SDS or SDS Plus shanks in its SDS Plus bit holder. SDS Max is a different, larger 18 mm shank.
Do I need a rotary hammer or a hammer drill?
Bosch says a rotary hammer's piston-driven hammer action exceeds a standard hammer drill, and it lists drilling masonry and setting anchors as typical SDS Plus jobs. A hammer drill such as the 2904-20 also drills wood and metal with ordinary bits and drives screws, and Milwaukee rates it for 5/8 in. in masonry.
Sources: Bosch's SDS-plus hammers, SDS-max hammers and cordless rotary hammers pages; Milwaukee's operator's manuals for the 2612-20 and 2904-20 and its 48-66-1370 adapter kit page; Hilti's Spindle TE-Y-BFH and TE 2-S pages; and DEWALT's hammer drill FAQ.