SDS Drill vs Combi Drill: When Do You Need an SDS?

The Hammer Drilling Question

Your combi drill has a hammer setting. It drills into brick. So why do SDS drills exist, and when do you need one?

How They Work Differently

Combi drill hammer action:

• Uses ratcheting mechanism to create vibration
• Bit vibrates rapidly while rotating
• Relies partly on you pushing to create impact
• Limited energy transfer

SDS hammer action:

• Pneumatic hammer mechanism
• Actual piston delivers real blows to the bit
• Impact happens regardless of push pressure
• Much more energy per blow
• Proper chiselling function on dedicated setting

The Real-World Difference

Drilling speed comparison:

Drilling a 10mm hole in concrete:

• Combi drill: 30-60 seconds of grinding away
• SDS drill: 5-10 seconds

That's not an exaggeration. The difference is that significant.

Hole size limitations:

• Combi drill: Practical limit around 8-10mm in hard masonry
• SDS: Standard bits up to 25mm+, core bits much larger

Material handling:

• Combi drill: Fine for soft brick, aircrete, light masonry
• SDS: Concrete, hard engineering brick, stone, aggregate

When You Need an SDS

Essential for:

• Regular drilling into concrete
• Holes larger than 10mm in masonry
• Hard engineering brick (the dark stuff)
• Stone and aggregate
• Multiple holes in a day
• Any chiselling work

Nice to have for:

• Faster drilling even in softer materials
• Less fatigue on heavy drilling days
• Professional appearance

When a Combi Drill Is Enough

Stick with combi for:

• Occasional masonry drilling
• Soft brick and blocks
• Small holes (6mm or under)
• Mixed work where versatility matters
• Budget constraints

SDS Types Explained

SDS Plus:

• Most common type
• Handles most drilling tasks
• Bit shank: 10mm diameter
• Good for holes up to 25mm or so
• Lighter, more manoeuvrable

SDS Max:

• Heavier duty
• Larger bit shank: 18mm diameter
• For larger holes and heavier chiselling
• Demolition and breaking work
• Heavier tool, more powerful motor

Most tradesmen need SDS Plus. SDS Max is for specific heavy applications.

Cordless SDS - Worth It?

Modern cordless SDS drills from DeWalt and Makita are excellent:

Advantages:

• No cables - work anywhere
• No generator needed on new builds
• Share batteries with other tools
• Performance nearly matches corded for most tasks

Considerations:

• Higher initial cost
• Battery drain on heavy use
• Corded still wins for all-day heavy drilling

For most trades, cordless SDS is now the default choice.

What About Rotary Hammers vs SDS?

SDS drills ARE rotary hammers. The terms are often used interchangeably. SDS refers to the chuck/bit system. Rotary hammer describes the mechanism.

The Trade-Specific View

Electricians: SDS essential. Constant drilling through masonry for cables.

Plumbers: SDS needed for pipe runs through walls.

Carpenters: Combi usually sufficient. SDS for specific jobs.

General builders: SDS essential. Core tool.

Decorators: Combi usually enough for fixings.

The Verdict

If you regularly drill into concrete or hard masonry, an SDS is a must. The time savings alone justify the cost. If masonry work is occasional and materials are soft, a good combi drill manages.

Most professional tradesmen end up with both: combi drill for wood, metal, and light masonry; SDS for the hard stuff. Check our power tools range for both options.