SDS Plus, SDS Max & Impact Drill Bits

What are SDS drill bits?

An SDS drill bit has a shank with grooves that lock into the chuck of a rotary hammer drill. The bit slides in and out of the chuck a little, so the hammer blows go straight into the bit while it turns, and its carbide tip breaks up concrete, brick and stone as it cuts. That is why SDS bits get through concrete far faster than a plain masonry bit in an ordinary drill, and why they need a hammer drill with the matching SDS chuck.

There are two SDS shanks, and a bit only fits the chuck it is made for:

• •SDS-Plus: a 10mm round shank with two round grooves that hold the bit in the chuck and two wedge grooves that drive it. Mungo states it suits hammer drills under 5kg and is the most widespread format. Our SDS-Plus bits run from 4 to 20mm.
• •SDS-Max: an 18mm round shank with two round grooves and three wedge grooves, for hammer drills over 5kg and bigger, deeper holes. Our SDS-Max bits run from 12 to 24mm.

3-cutter, Y-cutter or vacuum SDS bit?

The Power-TX 3-cutter (SP-3C and SX-3C) and Y-cutter (SX-YC) bits have a solid tungsten carbide tip with a self-centring point and a flute shape made to carry the dust out of the hole, and Hobson's data sheets for those bits say they do not seize up when they hit reinforcing steel. The SP-2V vacuum bit sheet makes neither claim. Choose by hole size and how you want to deal with the dust:

• •SP-3C SDS-Plus 3-cutter (4 to 20mm): Hobson lists it for concrete, masonry, asphalt and stone, for masonry and hammer drilling, and as suitable for drilling into ceilings.
• •SX-3C SDS-Max 3-cutter (12 to 20mm): for reinforced concrete, concrete and brick, and for drilling holes for chemical and mechanical anchors.
• •SX-YC SDS-Max Y-cutter (22 and 24mm): a Y-shaped drill point that Hobson says drills more quietly with less vibration, and is effective for large hole diameters.
• •Mungo MHP-Y SDS-Plus Y-cutter (18 and 20mm): Mungo's drills and chisels chart rates it as made for reinforced concrete, concrete, masonry, calcium silicate brick, brick, granite and marble, with a recessed carbide tip that stands up to reinforcing steel.
• •SP-2V SDS-Plus vacuum bit (6 and 8mm): a 2-cutter bit that drills and cleans the hole in one step. Hobson says it makes 90% less dust than a standard bit, does not jam when you pull it out of deep holes, suits drilling into ceilings and enclosed spaces, and has a universal adaptor that fits most common dust extractor vacuums (35mm vacuum end).

SDS-Plus and SDS-Max drill bit sizes

Every SDS bit we carry, by type and diameter, smallest to largest. The length is written working length over overall length: a 10 x 200/270 bit is 10mm across, drills up to 200mm deep and is 270mm long. For Mungo 2-cutter SDS-Plus bits, SDS-Max 6-cutter bits and hollow dust extraction bits, see our masonry drill bits page, which also has SDS-Max Y-cutter bits from 18 to 40mm for holes over 24mm.

Choosing the length: long SDS drill bits

Pick a working length a little longer than the hole you need. For an anchor, the anchor's instructions give the drill diameter and hole depth; add the thickness of anything you drill through first.

For deep holes and drilling through walls, the long SDS-Plus 3-cutter bits run to 400/470 (400mm working length) in 12, 14, 16, 18 and 20mm, and the SDS-Max 3-cutter bits to 400/550 in 14, 16, 18 and 20mm, with a 24 x 400/530 SDS-Max Y-cutter.

Step tip impact drill bits

The Power-TX Edge step tip impact bits are not SDS bits: they are M2 high speed steel twist bits that Hobson classes as impact bits, from 3 to 13mm. High speed steel bits are for drilling metal, timber and plastic, not masonry, so keep them out of concrete and brick.

Hobson lists each bit with two lengths, for example 28/62; the larger figure is the overall length given in the bit's description (3 x 62).

Drilling with SDS bits

1. Check for reinforcement with a detector and drill clear of it where you can. If you cannot avoid cutting reinforcement, consult a structural engineer first.
2. Check for pipes and cables before you drill. They usually run straight up and down from sockets and fittings.
3. Grease the bit's shank before fitting it into the chuck; Mungo says it extends the life of the drill.
4. Let the hammer do the work. Too much pressure, or holding the drill off-centre or at an angle, drops the drilling power.
5. Clean the dust out of the hole before setting an anchor, or use a vacuum bit, so the fixing reaches its holding value.

SDS drill bits in Adelaide

Allmat supplies SDS-Plus and SDS-Max drill bits, anchors and fixings to builders, concreters and trade across Adelaide and South Australia. Add the bits to a quote with the anchors and screws for the job, and we will price the lot.

Questions