SDS-plus and SDS-max are different rotary-hammer bit connection systems. An SDS-plus bit has a nominal 10 mm shank and suits compact and mid-sized rotary hammers. An SDS-max bit has a nominal 18 mm shank and suits larger, more demanding hammers and demolition equipment. They are not directly interchangeable.
When buying masonry bits it's easy to focus on the hole diameter and overlook the connection at the other end. The wrong shank won't fit your hammer's holder, even if the cutting tip is the perfect size. This guide covers the practical differences, what the numbers on a bit mean and what to check before you buy.
SDS Plus vs SDS Max: Quick Comparison
SDS-plus
Nominal 10 mm shank
Compact and general-purpose rotary hammers. Different grooves and locking geometry, so not directly interchangeable.
SDS-max
Nominal 18 mm shank
Larger rotary and demolition hammers. Different grooves and locking geometry, so not directly interchangeable.
| Feature | SDS-plus | SDS-max |
|---|---|---|
| Nominal shank diameter | 10 mm | 18 mm |
| Connection | SDS-plus tool holder | SDS-max tool holder |
| Typical tool | Compact to mid-sized rotary hammers | Larger rotary hammers and demolition hammers |
| Common work | Masonry anchor holes, installations, lighter chiselling | More demanding concrete drilling, heavier chiselling |
| Fits the other directly? | No | No |
| Shank size = hole diameter? | No | No |
What Is an SDS-Plus Drill Bit?
An SDS-plus bit is for a rotary hammer with an SDS-plus holder. Its 10 mm shank has a grooved locking arrangement that lets the hammer pass rotation and impact energy to the bit. Common accessories include masonry bits in different diameters and lengths, and compatible chisels where the hammer has an approved chiselling mode, so the tool manual remains the authority.
Bosch SDS Plus-3 Masonry & Concrete Bits
SDS-plus, many sizes. The 6mm is 100mm working length and 160mm overall (2608831008); a 14 x 200 x 260mm is also listed.
View at DBR Tools
DeWalt Extreme 2 SDS Plus Drill Bits
SDS-plus masonry bits from 5mm to 10mm in several lengths. Each size is a variant, so check the one you need.
View at DBR ToolsWhat Is an SDS-Max Drill Bit?
An SDS-max bit has a larger 18 mm shank and a different locking-groove arrangement, for heavier-duty rotary hammers and some demolition hammers. SDS-max doesn't automatically mean a bigger cutting diameter, because size ranges overlap: it's the tool connection, not the hole size, that identifies which bit belongs in the machine.
Some SDS-max machines are chiselling-only demolition hammers that don't rotate a drill bit at all, so check the tool's permitted functions as well as the shank.
Timco Addax 24 x 540mm SDS Max Bit
SDS-max, 18mm shank, 24mm tungsten-carbide 4-cutter head. 395mm working length, 540mm overall, for concrete, brick, block and stone.
View at DBR ToolsCan You Use an SDS-Plus Bit in an SDS-Max Drill?
Not directly. The shanks differ in diameter and locking geometry, so an SDS-plus bit won't lock into an SDS-max holder normally, and an SDS-max bit won't fit an SDS-plus holder. Adaptors exist for some combinations, but compatibility is model-specific, especially for chiselling or demanding drilling, so follow the equipment manufacturer's recommendations.
Shopping rule: identify the holder on your machine before comparing cutting sizes.
Does SDS-max drill faster?
Not as a stand-alone statement. SDS-plus and SDS-max identify connection systems, not drilling speed. A larger SDS-max hammer may have much more impact energy than a compact SDS-plus model, but that's a characteristic of the hammer, not the shank label. Look at the tool's stated drilling range and approved accessories.
Understanding SDS Drill Bit Sizes
Match your hammer's holder.
Match the hole you need.
Check both lengths.
A title such as 6 × 100 × 160 mm describes three dimensions: 6 mm cutting diameter (the nominal hole size), 100 mm working length (the part specified for drilling depth and dust evacuation) and 160 mm overall length (the whole bit, including the part held by the tool). The shank type is a separate specification, and cutting diameter is not shank diameter. Compare the exact dimensions to the job and the hammer's limits.
Two-cutter vs four-cutter bits
A two-cutter carbide-tipped bit may suit general masonry drilling where the maker approves it. A four-cutter design may give better hole geometry or resistance to binding in some reinforced-concrete work, depending on the product. Not every four-cutter bit is rated for reinforcing steel, so check the manufacturer's approval.
Which SDS Bit Should You Buy?
If you already own a rotary hammer, decide in this order: holder compatibility, then cutting dimensions, then material suitability.
| Your situation | What to check |
|---|---|
| You own an SDS-plus hammer | Choose bits labelled SDS-plus and approved for the task. |
| You own an SDS-max hammer | Choose SDS-max accessories suited to the tool's drilling or chiselling mode. |
| You need a different hole diameter | Compare cutting diameter, not shank diameter. |
| You need a deeper hole | Compare working length and the machine's limits. |
| You're choosing a bit and chisel kit | Confirm every accessory fits the holder and the tool supports the mode. |
- Confirm the holderLook for SDS-plus or SDS-max on the tool or manual.
- Check the materialChoose a bit specified for the intended masonry.
- Match the dimensionsReview cutting diameter, working depth and total length.
- Review suitabilityConsider bit condition, dust control and job limits.
Dust and safety. Rotary hammers and masonry bits create flying fragments, noise and significant dust. HSE identifies drilling concrete and mortar as a source of respirable crystalline silica. Use suitable dust extraction or suppression and PPE, follow the maker's instructions, and have hidden services or unfamiliar structural work assessed by a competent person.
Frequently Asked Questions
What is the main difference between SDS Plus and SDS Max?
The connection system. SDS-plus uses a nominal 10 mm shank; SDS-max uses 18 mm with different locking geometry. They fit different tool holders.
Are SDS-plus and SDS-max bits interchangeable?
Not directly. Some manufacturers offer approved adaptors for specific combinations, but never assume universal compatibility.
Is SDS Max always better for concrete?
No. It depends on the size and nature of the work and the hammer's rated capabilities. SDS-plus suits many concrete-drilling jobs.
Can I use SDS-max bits in a normal combi drill?
No. An SDS-max accessory is made for an SDS-max holder, not a three-jaw chuck. Choose accessories designed for your tool's holder and mode.
What does 6 × 100 × 160 mm mean on a drill bit?
Typically 6 mm cutting diameter, 100 mm working length and 160 mm overall length. Follow the maker's sizing convention.
Do SDS-plus and SDS-max use the same chisels?
No. The shank systems differ, and a chisel must match the tool holder and the hammer's operating-mode restrictions.
Final Verdict: SDS Plus or SDS Max?
The answer begins with the rotary hammer you already own. SDS-plus is common for compact and general-purpose masonry hammers; SDS-max is associated with larger equipment and heavier-duty work. Neither label tells you the hole diameter, working length or suitability for a material, so match the tool holder first, then compare the exact accessory specification.
Check current availability and your machine's compatibility before ordering.
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