SDS-Plus vs. SDS-Max: Sådan vælger du det rigtige borehammerbor til betonboring

Selecting the right rotary hammer bit for concrete drilling can mean the difference between a smooth, efficient job and a frustrating, time‑wasting struggle. The two most common shank systems—SDS‑Plus and SDS‑Max—are designed for different scales of work, and using the wrong one can damage your tool or produce poor results. Whether you are drilling small anchor holes for shelving or large diameters for structural rebar, understanding which system fits your needs is essential.

This guide breaks down the technical differences, performance characteristics, and real‑world applications of SDS‑Plus and SDS‑Max bits. You will also learn how to pair your bit choice with the right rotary hammer and battery platform for maximum productivity on the jobsite.

Understanding SDS‑Plus and SDS‑Max: What Sets Them Apart

Both SDS‑Plus and SDS‑Max are slotted drive systems that allow the bit to slide within the chuck while still transmitting rotary and hammering force. The key difference lies in shank diameter and length. SDS‑Plus shanks measure 10 mm in diameter and are typically used with lighter, more compact rotary hammers. They are ideal for drilling holes up to about 1 inch (25 mm) in diameter in concrete, brick, or block.

SDS‑Max shanks are larger at 18 mm in diameter and have a deeper groove design. They are built for heavy‑duty rotary hammers capable of drilling holes from 1 inch up to 2 inches or more. The larger shank provides greater torque transfer and durability, making SDS‑Max the go‑to choice for large‑diameter anchors, rebar penetration, and continuous drilling in hardened concrete.

Shank and Tool Compatibility: Why It Matters

Your rotary hammer’s chuck determines which shank type it can accept. Most compact and mid‑range rotary hammers use an SDS‑Plus chuck. These tools are lighter, easier to handle overhead, and well suited for tasks like drilling electrical box holes, installing wedge anchors, or running cable through concrete block walls. In contrast, SDS‑Max chucks are found on full‑size demolition hammers and large rotary hammers that deliver higher impact energy.

Mixing shank types is not possible without an adapter, and adapters can reduce efficiency and add play. Always check your tool’s specification before buying bits. If you own an M12‑ or M18‑powered rotary hammer, it will almost certainly accept SDS‑Plus bits. For the heaviest concrete work, a corded or high‑voltage cordless SDS‑Max hammer will be required. Choosing the right shank ensures your tool operates at its rated performance and prolongs bit life.

• Tip: Check the chuck type on your rotary hammer—most compact models are SDS‑Plus; heavy‑duty models are SDS‑Max.

Performance Factors: Speed, Hole Size, and Material Hardness

Drilling speed is influenced by the bit’s flute design, carbide tip geometry, and the hammer’s impact energy. SDS‑Plus bits typically have a 2‑cutter or 4‑cutter carbide tip. A 2‑cutter tip offers faster drilling in softer materials, while a 4‑cutter tip provides longer life in abrasive concrete. The Milwaukee 1/4 in. x 6 in. 2-Cutter SDS-PLUS Carbide Drill Bit is a great example of a 2‑cutter design that balances speed and durability, making it a staple for many concrete contractors.

SDS‑Max bits often feature reinforced carbide tips and wider flutes to clear dust efficiently on large holes. They are designed for sustained heavy use, such as coring or drilling multiple large‑diameter holes in reinforced concrete. Material hardness also plays a role—softer concrete or brick may be drilled with a cheaper bit, but for hard aggregate or rebar, a premium carbide bit is essential.

When to Choose SDS‑Plus Bits

Choose SDS‑Plus bits for most general‑purpose concrete drilling tasks. Common applications include installing concrete anchors for railing, shelving, or equipment, drilling holes for electrical boxes, and running conduit through block walls. The lighter weight of SDS‑Plus rotary hammers reduces user fatigue, making them ideal for overhead work and prolonged use on ladders.

SDS‑Plus bits are also a cost‑effective choice for small to medium jobs. They are available in diameters from 3/16 inch up to 1 inch, and lengths from 4 to 18 inches. If you primarily work on residential or light commercial sites, an SDS‑Plus system will cover the vast majority of your needs without the added expense and weight of SDS‑Max equipment.

• Best for: anchor holes, electrical boxes, light rebar, block walls, and small‐diameter drilling.

When to Choose SDS‑Max Bits

SDS‑Max bits are the right choice when your project involves large‑diameter holes (over 1 inch), deep drilling in high‑strength concrete, or frequent penetration of rebar. These bits are commonly used for installing heavy‐duty expansion anchors, dowels, and structural bolts in foundations, bridges, and industrial floors.

The larger shank provides greater stability and reduces bit wobble, leading to straighter holes and less fatigue on the tool. While SDS‑Max tools are heavier and more expensive, they deliver the impact energy needed for serious concrete work. For contractors who regularly drill large holes or work with high‑strength mixes, investing in an SDS‑Max system pays off in productivity and bit life.

• Best for: large anchors, rebar penetration, deep coring, and heavy structural concrete.

Bit Quality and Durability: What to Look For

The quality of the carbide tip and flute design directly affects drilling speed and bit longevity. Look for bits with sharp, brazed carbide cutting edges and hardened steel bodies. A well‑designed flute efficiently removes dust, preventing the bit from jamming. The 1/4 in. x 6 in. 2-Cutter SDS-PLUS Carbide Drill Bit from Milwaukee uses a two‑cutter geometry that drills quickly while maintaining a long service life.

For SDS‑Max bits, consider bits with reinforced brazing and thicker carbide, as they encounter higher stress. Avoid generic or unbranded bits; they often use lower‐grade carbide and can dull quickly, costing you time on the jobsite. Stick with reputable brands that offer clear specifications and warranty coverage.

Battery Considerations for Cordless Rotary Hammers

If you use cordless rotary hammers, the battery platform matters nearly as much as the bit. Milwaukee’s M12 system powers compact SDS‑Plus rotary hammers that are perfect for lighter drilling. For extended runtime and peak performance, pairing your tool with a high‑capacity battery, such as the M12 12-Volt Lithium-Ion XC Extended Capacity Battery Pack 4.0Ah, ensures you can drill more holes per charge without sagging performance.

For larger jobs requiring SDS‑Max tools, M18 High Output or REDLITHIUM FORGE batteries are recommended to supply the high current draw needed for heavy drilling. Always match your battery capacity to the demands of the tool and the bit size you are driving to avoid premature battery shutdown in the middle of a hole.

• Tip: For compact SDS‑Plus rotary hammers, an M12 XC 4.0Ah battery provides a great balance of weight and runtime.

Choosing between SDS‑Plus and SDS‑Max rotary hammer bits comes down to the scale of your concrete work. For most routine drilling tasks, an SDS‑Plus system offers the right mix of portability and power. When your project demands larger holes or heavier material, step up to SDS‑Max. Whichever you choose, investing in quality bits and compatible batteries will save you time and frustration on every jobsite.