Hammer Drill Bit Types: SDS Plus, SDS Max and Masonry Bits Explained

Hammer drill bits come in two families: straight or hex-shank masonry bits for a standard hammer drill chuck, and SDS bits (SDS Plus and SDS Max) for rotary hammers. The shank decides which tool the bit fits; the tip decides what it cuts and how long it lasts.

Key points:

• SDS Plus has a 10 mm shank and covers most anchor holes, roughly 5/32" to 1-1/8".
• SDS Max has an 18 mm shank for larger holes, core bits and heavy chiseling.
• SDS Plus and SDS Max are not interchangeable, and neither fits a standard three-jaw drill chuck.
• 4-cutter and full-head carbide bits cost more but drill rounder holes and survive hitting rebar better than 2-cutter bits.

Hammer drill bit types at a glance

Bit type	Shank	Fits	Typical hole size	Use it for
Carbide-tipped masonry bit	Round or hex, straight	Hammer drill with a three-jaw chuck	Up to about 1/2"	Occasional small anchor holes in brick, block and mortar
SDS Plus bit	10 mm, slotted	SDS Plus rotary hammer	5/32" to 1-1/8"	Daily anchor drilling in concrete: wedge anchors, drop-ins, concrete screws
SDS Max bit	18 mm, slotted	SDS Max rotary hammer	1/2" to 2"	Large and deep holes, through-holes for pipe and conduit, rebar dowels
Core bit	SDS Max or spline	Large rotary hammer	About 2" to 6"	Penetrations for pipe, conduit and ductwork
Chisels and points	SDS Plus or SDS Max	Rotary hammer with hammer-only mode	n/a	Chipping, tile removal, channeling and demolition

Masonry bits for a standard hammer drill

A hammer drill uses a normal keyless chuck and a clutch mechanism that taps the bit forward as it spins. It takes straight-shank carbide-tipped masonry bits. This setup is fine for a few small holes in brick, block or mortar. In poured concrete it is slow, and the chuck can slip on larger bits.

SDS Plus bits

SDS Plus is the standard for anchor drilling. The 10 mm shank has slots that lock into the tool, so the bit slides back and forth while a piston drives it. That delivers far more impact energy than a hammer drill, with no chuck to tighten. Most SDS Plus rotary hammers are rated up to 1" or 1-1/8" in concrete; the Milwaukee 1-1/8" SDS Plus Rotary Hammer Kit (5268-21) is a typical example.

SDS Max bits

SDS Max uses a thicker 18 mm shank to transmit much higher impact energy. It is the system for holes above about 1", deep holes, core bits and serious chiseling. SDS Max rotary hammers are heavier and are usually run with two hands on the floor or wall rather than overhead all day. See rotary hammers and demolition hammers.

2-cutter, 4-cutter and full-head carbide

Tip	Strengths	Choose it when
2-cutter	Fast, lowest cost	Plain concrete, block and brick with no rebar
4-cutter	Rounder holes, less jamming, better life on rebar	Reinforced concrete and anchors that need an accurate hole diameter
Full-head (solid) carbide	One-piece carbide head, longest life	Production anchor drilling and frequent rebar contact

How to read bit sizes

SDS bits are listed with three numbers, for example 1/4" x 4" x 6": the diameter, the usable drilling depth and the overall length. Match the diameter to the anchor manufacturer's specification, and choose a usable length that covers the anchor embedment plus the thickness of whatever you are fastening.

Choosing the right bit for the job

Job	Bit
3/16" and 1/4" concrete screws for boxes, straps and clips	SDS Plus 2-cutter, short length
3/8" to 5/8" wedge and drop-in anchors	SDS Plus 4-cutter or full-head carbide
Holes over 1", rebar dowels, deep through-holes	SDS Max 4-cutter
2" to 6" penetrations for pipe and conduit	SDS Max or spline core bit
Removing tile, chasing a channel, breaking out concrete	Flat chisel or bull point in hammer-only mode

Bits in stock at Tool Mart

Bit	System	Price
Milwaukee M/2 2-Cutter SDS Plus 1/4" x 4" x 6" (48-20-7431)	SDS Plus, 2-cutter	See price
DeWALT Solid Rock Carbide SDS Plus 1/4" x 4" x 6" (DW5517)	SDS Plus, solid carbide	See price
DeWALT 4-Cutter SDS Plus 3/4" x 8" x 10" (DW5474)	SDS Plus, 4-cutter	See price
DeWALT SDS Max 5/8" x 8" x 13-1/2" (DW5806)	SDS Max	See price
Milwaukee SDS Max and Spline Thick Wall Core Bit 4" (48-20-5155)	Core bit	See price

See all rotary hammer bits and chisels. For twist, step and spade bits, read types of drill bits and their uses.

Where to buy SDS and hammer drill bits in Houston and San Antonio

Tool Mart stocks SDS and hammer drill bits at both Texas stores, open Monday to Friday, 7:30 AM to 5:00 PM. Order online for same-day pickup or call the counter to check stock before you drive over.

• Houston area: 13721 S. Gessner #200, Missouri City, TX 77489 · 713-222-8665
• San Antonio: 10568 Sentinel St, San Antonio, TX 78217 · 210-655-6116

Outside Houston and San Antonio? We ship by UPS Ground and freight: browse rotary hammer bits and chisels.

Frequently asked questions

Can I use an SDS bit in a regular hammer drill?

No. The slotted SDS shank is made to slide in an SDS chuck and will not grip properly in a three-jaw chuck. Use straight-shank masonry bits in a hammer drill.

What is the difference between SDS Plus and SDS Max?

Shank size and capacity. SDS Plus has a 10 mm shank for holes up to about 1-1/8"; SDS Max has an 18 mm shank for larger holes, core bits and heavy chiseling. The two do not fit each other's tools.

Do I need a 4-cutter bit?

For anchors in reinforced concrete, yes, it is worth it. A 4-cutter tip drills a rounder hole and is far less likely to jam or chip when it meets rebar.

Why did my masonry bit stop cutting?

The carbide tip is worn or chipped, usually from heat or from hitting steel. Let the tool do the work without leaning on it, clear dust from the hole, and replace the bit once the tip is rounded over.

What size bit do I need for a 3/8" wedge anchor?

Wedge anchors normally use a bit the same diameter as the anchor, so 3/8". Always confirm with the anchor manufacturer's instructions, since concrete screws and some other anchors use a smaller bit than their nominal size.