How to use an SDS max drill bit in masonry
Updated: 2026-10-23
How to use an SDS max drill bit, on a brick wall or a concrete floor, is mostly about dust, heat and what is buried in the masonry. Packed flutes stop the hole. Concrete dust can contain respirable crystalline silica, so treat it as silica until you know otherwise. This page does not rank the five listings on the [SDS max drill bit comparison](/hub/drilling-and-accessories/sds-max-drill-bit). If the shank is SDS plus, that mismatch is [SDS max vs SDS plus](/hub/drilling-and-accessories/sds-max-drill-bit/sub/sds-max-drill-bit-vs-sds-plus).
How to use an SDS max drill bit, on a brick wall or a concrete floor, is mostly about dust, heat and what is buried in the masonry. Packed flutes stop the hole.
How to use an SDS max drill bit, on a brick wall or a concrete floor, is mostly about dust, heat and what is buried in the masonry. Packed flutes stop the hole. Concrete dust can contain respirable crystalline silica, so treat it as silica until you know otherwise. This page does not rank the five listings on the SDS max drill bit comparison. If the shank is SDS plus, that mismatch is SDS max vs SDS plus.
Our top picks
| Badge | Product | Stated length | Flutes | Tip | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Keewaki Keewaki 20 x 400 mm | Title 400 mm; one bullet 340 mm | Not stated | 4-cutter cross tip | 6.8 | about £17.99 | View offer |
| Best value |  UK Drills UK Drills 18 x 330 mm | 330 mm; working length not split | 2, spiral | 4-cutter, taper point, 118 degrees | 5.6 | about £14.89 | View offer |
| Alternative |  UK Drills UK Drills 25 x 550 mm | 550 mm; working length not split | 2, spiral | 4-cutter cross head | 5.6 | about £26.99 | View offer |
On this page
Seat the bit and start the hole slowly
Push the SDS max shank in until it clicks and stays. Hammer drilling is the position for a masonry hole. Set the depth against the fixing sheet. Part of the shank remains inside the chuck, so a 400 mm title is not 400 mm of hole. Which length to buy is on the SDS max drill bit buying guide.
HSE sheet CN3 tells you to start slowly. Leaning on the machine packs the flutes. A 25 mm bit in a floor slab is where that lean feels useful and is the mistake.
Clear the flutes while you drill
CN3 says to withdraw the bit while it is still rotating, so the flutes carry debris out. On a 20 mm hole in dense block, a few centimetres and then a withdrawal is a workable rhythm. They do not extract dust through the shank. Heller's Duster Expert SDS-max and Milwaukee's dustless SDS-max bits are hollow extraction bits, which are different products.
Capture the dust
Where it is reasonably practicable, CN3 and CIS36 call for on-tool extraction of M or H class. HSE describes short-duration drilling as about 15 to 30 minutes in a day. When extraction is not used, or drilling is the main job, use respiratory protective equipment with an assigned protection factor of at least 20. CIS69 says the hood has to sit close to the work, the hoses tight, and the unit emptied.
Trigger time is separate. The Control of Vibration at Work Regulations 2005 set an action value of 2.5 m/s² A(8) and a limit of 5 m/s² A(8). HSE's rule of thumb for hammer-action tools is about 15 minutes toward the action value and about one hour toward the limit.
Heat, water and services
The UK Drills pages ask whether water is needed and do not answer. Do not copy a quench from a US review about another size. Short withdrawals while the bit still rotates are the cooling step these solid bits allow. If the carbide has cracked, stop and change the bit.
HSE's CIS65 says that if cable routes in a wall are unknown, isolate first. In a slab or in the ground, HSG47 is the reference for plans and locating. A metallic click is not a dust problem. What a reinforced concrete title does not guarantee is on the SDS max drill bit for reinforced concrete page.
We followed HSE CN3, CIS36, CIS69 and the vibration regulations. We did not drill these bits in a lab. A qualifying purchase through our links can earn a commission at no extra cost to you. Updated 22 October 2026.
Common questions
How do I drill with an SDS max bit without burning the tip?
Seat the shank until it clicks, start slowly, and let the hammer hit rather than leaning on the machine. Withdraw the bit while it is still rotating, before the flutes pack, which is the rhythm in HSE CN3. A 20 mm hole in dense block may need that withdrawal every few centimetres. If the bit slows or smokes, stop and let it cool in air. These listings do not give you a water-cooling instruction to follow.
Should I use water to cool it?
The UK Drills pages ask whether water is needed for cooling and do not answer. Leave that question unanswered. Do not treat a US review that mentions heat, or a quench, as a UK method, because those reviews mostly describe other sizes and are not a test of this bit. The step you can take from CN3 is to clear the flutes while the bit rotates and to pause when the tip gets hot.
What mask or extractor does HSE describe for concrete drilling?
CN3 and CIS36 call for M or H class on-tool extraction where that is reasonably practicable. They describe about 15 to 30 minutes of drilling in a day as short duration. When extraction is not used, or drilling is the main job, they call for RPE with an APF of at least 20. CIS69 adds that the hood must be close to the work, the hoses tight, and the unit emptied. A solid bit does not include that hood.
How long can I run a rotary hammer?
HSE's rule of thumb for hammer-action tools is about 15 minutes of trigger time toward the 2.5 m/s² A(8) action value, and about one hour toward the 5 m/s² A(8) limit, under the Control of Vibration at Work Regulations 2005. That clock is on the hammer, not on the drill bit. CN3's 15 to 30 minutes is a separate dust figure for short-duration drilling.
What do I check before drilling a wall or a slab?
Confirm the shank is SDS max and seated, and confirm the mode is hammer drilling. In a wall, if you do not know the cable routes, isolate first, which is the CIS65 point. In a slab or in the ground, use plans and locating as HSG47 describes before the bit goes in. Mark the fixing depth, because the title length is not the hole.
Related pages
Sources
Public UK and manufacturer pages used for shank, dust, vibration and anchor-bit geometry, plus the amazon.co.uk listings for the five ASINs. Last checked on 22 October 2026.
- Heller Tools, Shanks (retrieved 22 October 2026)
- HSE CN3, Construction dust: drilling (retrieved 22 October 2026)
- HSE CIS36, Construction dust (retrieved 22 October 2026)
- HSE, Hand-arm vibration: assess the risks (retrieved 22 October 2026)
- HSE INDG175, Hand-arm vibration (retrieved 22 October 2026)
- HSE, Electrical systems on construction sites (retrieved 22 October 2026)
- Bosch Professional GB, PRO SDS max-7 drill bit (retrieved 22 October 2026)
- PGM, Check of standard drill bits (retrieved 22 October 2026)
- PGM, Marking of drill bits (retrieved 22 October 2026)