SDS-max shank

How to choose an SDS-max core drill bit

When choosing an SDS-max core drill bit, it is crucial to clarify how often and under what conditions you will be drilling. Individual types differ in design, the way the core bit is connected to the shank, and overall durability under load.

Disassemblable SDS-max Core Drill Sets are suitable when you want to work with multiple diameters and use one shank. They offer flexibility and are practical for assembly and installation work.

Compact SDS-max Core Drill Bits are the choice when you need maximum stability, long service life, and high durability for demanding drilling. Here, the shank and the core bit form one solid unit.

VARIANT system core drill bits are designed for intensive professional use. They allow combining individual components and changing the shank using adapters within the VARIANT system.

The choice of a specific type therefore mainly depends on the difficulty of the job and the expected tool load.

Where and how SDS-max core drill bits are used in practice

Core drill bits with SDS-max shank are mainly used for more demanding construction, assembly, and installation work where it is necessary to create a larger-diameter hole with a clean and precise edge. Typically, this includes electrical installations, technical penetrations for cables, pipes and piping, or preparing holes for technological equipment in walls and ceilings made of concrete and solid masonry.

The most common use of SDS-max core bits is for electrical installation openings, especially where larger or deeper boxes are used. The standard diameter remains 68 mm, but 80 mm is also used very frequently. It provides a larger installation allowance, makes it easier to seat the box accurately and finish the opening, or allows multiple runs to be combined in one place. Other commonly used diameters are roughly in the range from 40 to 100 mm, depending on the type of installation and the structure.

SDS-max core drill bits are used where drilling with a twist drill bit would be inefficient, time-consuming, or would lead to damage of the surrounding material. Compared to twist drill bits, they allow you to create a precise hole without chiseling and additional finishing. However, it is important to consider that core bits are structurally limited in depth and are not intended for long through-drilling.

In practice, SDS-max core bits are used together with powerful rotary hammers or combi hammers designed for high impact energy and long-term load. Especially with larger diameters or drilling in hard concrete, the advantage of the SDS-max system becomes most apparent – drilling progresses smoothly, the machine is not unnecessarily overloaded, and the work maintains a steady pace.

When it comes to repeated drilling of larger diameters, tougher conditions, or hard concrete, it is worth choosing SDS-max not only because of performance, but also because of the core bit service life and working comfort. The right combination of machine and core bit type has a crucial impact on the result and overall efficiency of this drilling method.

How to work with SDS-max core drill bits

Core drill bits with SDS-max shank are used exclusively with powerful rotary hammers or combi hammers that are structurally designed to work with high impact energy. Unlike twist drill bits, they do not remove material across the entire area of the hole, but only along its perimeter. That is why they require a different work procedure, stable machine guidance, and sufficient power.

With most SDS-max core bits designed for concrete, work is performed with hammer action, especially when drilling into hard concrete, reinforced concrete, and solid masonry. The pneumatic hammer action of the rotary hammer enables smooth drilling progress without the need for excessive feed pressure. The core bit should advance primarily due to the hammer energy and the tool design, not operator force.

The following recommendations are worth considering if you want the work to proceed smoothly, with a good result, and without unnecessary damage to the core bit, the machine, or the drilled material.

Recommendations for the drilling procedure

Hammer action and its role in practice
With SDS-max core drill bits, hammer action is essential especially when drilling into harder materials. Drilling happens primarily due to the impact energy of the rotary hammer. Excessive feed pressure will not speed up the work and can lead to overheating or damage to both the core bit and the machine.

Guiding the core bit and feed pressure
Hold the machine stable and perpendicular to the drilled surface. Do not push on the core bit – let it work with its cutting edge and the machine’s hammer action. Proper technique means smooth guidance without wobbling and without trying to force your way through the material.

Gradual drilling and material removal
Work gradually while drilling. Pull the core bit out of the hole regularly so the drilled material can be released. If material accumulates inside the core bit, drilling slows down, friction increases, and the tool overheats.

Work in hard concrete and masonry
When drilling into hard concrete, reinforced concrete, or areas with varying structure, maintain smooth progress and do not try to overcome resistance by force. If drilling does not progress evenly, it is advisable to check whether the selected core bit type is suitable or consider using a more powerful machine.

Rules for work

• Do not push on the core bit – let the hammer action and the tool design do the work.
• Work smoothly and without wobbling the machine.
• Pull the core bit out of the hole regularly so it does not clog with drilled material.
• If drilling does not progress smoothly, check whether the selected core bit type is suitable or whether the machine has enough power.
• For larger diameters, work patiently and without unnecessary rushing.

Safety notice

• Use safety glasses, and for longer work also hearing protection.
• Before drilling into walls and ceilings, always check whether electrical cables, water, or gas lines run in the area.
• Hold the machine firmly with both hands, especially when the core bit bites.
• When drilling overhead or into floors, take extra care due to falling material and dust.
• Regularly check the condition of the core bit – a damaged or heavily worn core bit increases the risk of injury and machine damage.

How is the range further structured?

Core drill bits with SDS-max shank are further divided by design and intended use:

• Disassemblable SDS-max Core Drill Sets
  Sets consisting of a core bit, a shank, and a pilot drill. They allow combining different diameters with one shank and provide a universal solution for a wide range of tasks.
• Compact SDS-max Core Drill Bits
  Core bits where the shank and body form one unit. They are characterized by high stability, durability, and long service life in demanding drilling.
• VARIANT system core drill bits
  A system solution designed for maximum load and long-term professional use. Thanks to interchangeable adapters, they allow combination with different shank types within the VARIANT system.

After selecting the specific branch, you then choose the diameter and core bit design according to the specific application.