Masonry Drill Bits: Slow Spiral, Cyclo Twist or Hammer-Rated

Look at the collar on your drill before you buy a bit. A drill icon means rotation only. A hammer icon means the chuck also pounds forward thousands of times a minute. A slotted chuck with no key means an SDS rotary hammer. That setting decides which masonry bit cuts and which one just gets hot.

People call these bits masonry bits, concrete bits, hammer drill bits, carbide-tipped bits, percussion bits and roto percussion drills. Our store sells three straight-shank lines: ITM's HD Roto Hammer (heavy-duty roto percussion), ITM's slow spiral (standard roto percussion), and Tru-Cut's Cyclo Twist fast spiral bits. All three fit a three-jaw chuck. None of them fits an SDS chuck.

Which masonry drill bit does your drill take?

Your drill's setting picks the masonry drill bit: a hammer-rated bit when the hammer is on, a fast spiral bit when it's off, and an SDS bit in an SDS rotary hammer. The slow spiral is the one bit that works in either setting of a three-jaw drill. Here is what each maker says.

Collar setting	HD Roto Hammer (ITM)	Slow spiral (ITM)	Cyclo Twist (Tru-Cut)	SDS-Plus (ITM)
Drill / driver, no hammer	No. ITM: "will not perform with rotation only"	Yes	Best fit. Tru-Cut: fast spiral "for rotary drilling"	Doesn't fit the chuck
Hammer drill, hammer off	No	Yes	Best fit	Doesn't fit the chuck
Hammer drill, hammer on	Best fit. ITM: "made for machines with percussion"	Yes. ITM: "Use with Percussion"	Turn the hammer off, or use the HD bit	Doesn't fit the chuck
SDS rotary hammer	Doesn't fit the chuck	Doesn't fit the chuck	Doesn't fit the chuck	Yes

Poured concrete needs the hammer. Rotation alone polishes the bottom of the hole and burns the carbide. Brick, block and mortar cut fine with rotation, so a cordless drill/driver and a Cyclo Twist bit will set plastic anchors in a block wall all day. For hard stone and pavers, turn the hammer on.

The HD Roto Hammer is made in France and switches to a hex shank from 5/8 in. up, so it won't spin in the chuck under load. Cyclo Twist is made in the USA by Tru-Cut. Tru-Cut describes Cyclo Twist as a rotary bit, so run it with the hammer off. If your job needs the hammer, the HD bit is the one built for it.

Is a "rotary hammer" bit made for a rotary hammer?

No. Our HD Roto Hammer bits have a round or hex shank for the three-jaw chuck of a hammer drill, not the slotted shank an SDS rotary hammer needs. ITM's own heading for them is "Roto Percussion Drills, Heavy Duty," and its catalog says "Made for Hammer Drills!"

A hammer drill and a rotary hammer are different tools. A hammer drill makes its blows with two ribbed discs in the gearbox, and it takes ordinary straight-shank bits. A rotary hammer drives a piston, hits much harder, and takes SDS-Plus or SDS-Max bits that slide in the chuck. If your bit pushes into the chuck and clicks, read SDS Plus vs SDS Max. The 1/4 x 6-1/4 in. SDS-Plus bit is 715S61664.

Slow spiral vs fast spiral: what does the flute change?

The flute is the spiral groove that carries dust out of the hole. A fast spiral has more turns per inch and lifts dust out quickly. A slow spiral has fewer turns and leaves a thicker core, which takes the pounding of a hammer drill better.

Trait	Slow spiral	Fast spiral (Cyclo Twist)
Turns of the flute	Fewer, gentler twist	More, tighter twist
Dust removal	Steady	Fastest, so the tip stays on fresh material
Core	Thicker, takes hammer blows	Thinner
Drill	Plain drill or hammer drill (ITM)	Rotary drilling (Tru-Cut)
Longest we stock	24 in.	48 in.

How do you tell a masonry bit from a regular drill bit?

A masonry bit has a flat carbide tip brazed into the end, wider than the steel body behind it. A metal or wood twist bit is one piece of steel ground to a sharp point. Run your thumb across the tip: a masonry bit feels like a small chisel, and the carbide is often a different color from the body. ITM's slow spiral has a gold-colored head.

Look at	Masonry drill bit	Metal or wood twist bit
Tip	Flat carbide insert, like a small chisel	Ground steel point, 118° or 135°
Width at the tip	Wider than the body	Same as the body
Cuts by	Crushing and scraping	Slicing
In wood	Drills slowly and leaves a ragged hole	Clean hole

What size bit for a Tapcon, wedge, sleeve or drop-in anchor?

A 1/4 in. Tapcon takes a 3/16 in. masonry bit, and a 3/16 in. Tapcon takes a 5/32 in. bit. Drill the hole at least 1/2 in. deeper than the screw will go. Wedge and sleeve anchors take a bit the same size as the anchor. Drop-in anchors take a bit one size up, drilled to the anchor's length.

Fastener	Bit size (in.)	Hole depth	Hammer on: HD Roto Hammer	Hammer off: Cyclo Twist	Either: slow spiral
3/16 in. Tapcon	5/32	1/2 in. deeper than the screw goes	700061064, 6 in., $3.51	F1563, 3 in., $3.25	—
1/4 in. Tapcon	3/16	1/2 in. deeper than the screw goes	700061264, 6 in., $3.08	F1876, 6 in., $2.55	502SP6001, 6 in., $2.77
1/4 in. wedge or sleeve anchor	1/4	At least 1/2 in. past the embedment	700061664, 6 in., $3.54	F2506, 6 in., $2.84	502SP6002, 6 in., $3.09
3/8 in. wedge or sleeve anchor	3/8	At least 1/2 in. past the embedment	700062464, 6 in., $4.57	F3756, 6 in., $4.44	502SP6004, 6 in., $4.14
1/2 in. wedge or sleeve anchor	1/2	At least 1/2 in. past the embedment	700063264, 6 in., $7.23	F5006X3/8, 6 in., $5.76	502SP6007, 6 in., $4.50
5/8 in. wedge anchor	5/8	At least 1/2 in. past the embedment	700064064, 6 in., $10.92	F6256, 6 in., $11.02	502SP6009, 6 in., $8.13
3/4 in. wedge anchor	3/4	At least 1/2 in. past the embedment	700064864, 6 in., $13.93	F7506, 6 in., $13.01	502SP6010, 6 in., $10.15
1/4 in. drop-in anchor	3/8	The anchor's length, so it sits flush	700062464, 6 in., $4.57	F3756, 6 in., $4.44	502SP6004, 6 in., $4.14
3/8 in. drop-in anchor	1/2	The anchor's length	700063264, 6 in., $7.23	F5006X3/8, 6 in., $5.76	502SP6007, 6 in., $4.50
1/2 in. drop-in anchor	5/8	The anchor's length	700064064, 6 in., $10.92	F6256, 6 in., $11.02	502SP6009, 6 in., $8.13

Prices are per bit. Check the anchor's box for its own hole size; a few brands differ. Drop-in sizes match ITM's stop bits, which are labeled by anchor.

On an SDS rotary hammer, a stop bit drills a drop-in hole to the right depth every time: STP-617 for 1/4 in. drop-ins ($16.76), STP-827 for 3/8 in. ($19.55) and STP-1033 for 1/2 in. ($23.78). For nail-in ceiling anchors, the SDS-HD1 anchor driver ($34.90) drives them from the same SDS-Plus hammer.

Which masonry bit reaches through a block wall or foundation?

Pick a bit whose drilling depth is longer than the wall is thick, and it goes through in one pass. A bit that reaches past the middle can drill from both sides. An 8 in. block wall needs about 9 in. of drilling depth, and a 12 in. poured foundation about 13 in. The drilling depth is the fluted part of the bit, always shorter than its overall length.

Size (in.)	Line	SKU	Overall length (in.)	Drilling depth (in.)	Shank (in.)	Price per bit	Buy at least
1/4	HD Roto Hammer	700081664	12	11	1/4	$8.03	5
1/4	HD Roto Hammer	700024166	24	23	1/4	$15.94	4
1/4	Slow spiral	502SP1814	18	16	1/4	$9.05	4
1/4	Cyclo Twist	X25036	36	—	—	$24.05	2
3/8	HD Roto Hammer	700082464	12	11	3/8	$9.28	4
3/8	Slow spiral	502SP1838	18	16	3/8	$12.38	4
3/8	Cyclo Twist	X37548	48	—	—	$43.20	1
1/2	HD Roto Hammer	700083264	12	10	3/8	$13.51	4
1/2	HD Roto Hammer	700024326	24	23	3/8	$20.83	2
1/2	Slow spiral	502SP1812	18	16	3/8	$13.80	4
1/2	Cyclo Twist	X50018	18	—	—	$11.32	4
5/8	HD Roto Hammer	700084064	12	11	Hex 3/8	$17.23	4
5/8	Slow spiral	502SP2458	24	22	3/8	$33.73	1
5/8	Cyclo Twist	X62524	24	—	—	$20.94	2
3/4	HD Roto Hammer	700084864	12	11	Hex 1/2	$19.82	2
3/4	HD Roto Hammer	700024034	24	23	Hex 1/2	$37.71	1
3/4	Slow spiral	502SP1834	18	16	1/2	$24.54	2
3/4	Cyclo Twist	X75018	18	—	—	$20.18	2
1	Slow spiral	502SP1208	12	10	1/2	$24.13	2
1	Slow spiral	502SP1801	18	16	1/2	$32.43	2

For a 1 in. sleeve hole through a 12 in. foundation, the 1 x 18 in. slow spiral (502SP1801) goes through in one pass with the hammer on. It needs a 1/2 in. chuck. Over 1-1/8 in., no straight-shank masonry bit is made: use a grit or diamond hole saw in block (see carbide hole saw vs bi-metal vs grit), or an SDS-Max core bit in a poured wall.

Only Cyclo Twist comes longer than 24 in.: 1/4 in. at 30 and 36 in., and 3/8 in. at 36 and 48 in. Tru-Cut doesn't publish Cyclo Twist drilling depth, so allow for the length the chuck grips. Run long bits slowly and start the hole with a short bit; a long, thin bit whips if you start it in open air. For wire runs through framing, a bell hanger or flex bit is the better tool.

What does a masonry bit cost per hole?

A 1/4 x 6 in. masonry bit costs $2.84 to $3.54 here, depending on the line. The cheapest bit isn't always the cheapest order. Cyclo Twist sells in twelves with a 24-bit minimum, so the smallest 1/4 x 6 in. order is $68.16. The HD bit costs more per piece but starts at 10 bits, $35.40.

Size x 6 in.	Cyclo Twist ($ per bit)	Slow spiral ($ per bit)	HD Roto Hammer ($ per bit)
3/16	2.55	2.77	3.08
1/4	2.84	3.09	3.54
3/8	4.44	4.14	4.57
1/2	5.76	4.50	7.23
5/8	11.02	8.13	10.92
3/4	13.01	10.15	13.93
1	24.97	16.35	19.57

From 3/8 in. up, the slow spiral is the cheapest bit per piece. If you drill the same size every day, buy the 25-pack: it saves 8 to 16% per bit on every ITM size that comes in one.

Bit	Single	Smallest single order	25-pack	Per bit in the pack
3/16 x 6 in. HD Roto Hammer	700061264, $3.08	12 bits, $36.96	700061264-B, $69.29	$2.77
1/4 x 6 in. HD Roto Hammer	700061664, $3.54	10 bits, $35.40	700061664-B, $79.56	$3.18
3/16 x 4 in. slow spiral	502SP4002, $1.66	22 bits, $36.52	502SP4002-B, $35.03	$1.40
1/4 x 4 in. slow spiral	502SP4003, $1.80	20 bits, $36.00	502SP4003-B, $39.37	$1.57
1/4 x 6 in. slow spiral	502SP6002, $3.09	12 bits, $37.08	502SP6002-B, $69.44	$2.78
3/8 x 6 in. HD Roto Hammer	700062464, $4.57	8 bits, $36.56	700062464-B, $102.66	$4.11
1/2 x 6 in. HD Roto Hammer	700063264, $7.23	5 bits, $36.15	700063264-B, $162.79	$6.51

The 3/16 x 4 in. slow spiral 25-pack costs less than the 22 single bits it replaces. The 3/16 x 6 in. HD bit is our best-selling masonry bit, because it drills the hole for a 1/4 in. Tapcon.

"The masonry bit we ship most is the 3/16 x 6 in. HD Roto Hammer, because it's the hole for a 1/4 in. Tapcon. Buy the 25-pack and you're not driving to the supply house for one bit."

David Castro, President, Eldorado Tools

Which masonry bit should you buy for your job?

Buy for the drill in your hand and the fastener in your pocket. These are the bits we'd pick, by trade and job.

Job	Trade	Pick	Price per bit	Fits
1/4 in. Tapcons in poured concrete, hammer on	Electrical, HVAC	700061264 HD Roto Hammer, 3/16 x 6 in.	$3.08, or $2.77 in a 25-pack	Any three-jaw hammer drill
3/8 in. wedge anchors for strut, hangers and boxes	Electrical, Plumbing	700062464 HD Roto Hammer, 3/8 x 6 in.	$4.57	Hammer drill
1/2 in. wedge anchors for pier brackets and ledgers	Foundation	700063264 HD Roto Hammer, 1/2 x 6 in.	$7.23	Hammer drill, 3/8 in. shank
Plastic anchors in block or brick, cordless drill/driver	Anyone	F2506 Cyclo Twist, 1/4 x 6 in.	$2.84, sold in 12s	Any drill, hammer off
One bit for a crew with mixed drills	Anyone	502SP6002 slow spiral, 1/4 x 6 in.	$3.09, or $2.78 in a 25-pack	Plain drill or hammer drill
3/4 in. line through an 8 in. block wall	Plumbing	700084864 HD Roto Hammer, 3/4 x 12 in.	$19.82	Hammer drill, hex 1/2 in. shank
1 in. sleeve through a 12 in. foundation	Plumbing, Foundation	502SP1801 slow spiral, 1 x 18 in.	$32.43	1/2 in. chuck
Cable through a long run of brick	Low voltage, security	X37548 Cyclo Twist, 3/8 x 48 in.	$43.20	Rotary, hammer off
Any hole with an SDS rotary hammer	Anyone	715S61664 SDS-Plus, 1/4 x 6-1/4 in.	See the SDS guide	SDS-Plus chuck

Why did my masonry bit stop cutting?

Most stalled masonry bits are a setting problem, not a dull bit. Check the collar and the direction switch before you buy another bit.

What you see	Likely cause	Fix
Smoke, no progress, in concrete	Hammer off, or drill in reverse	Set forward and the hammer icon, and use an HD bit
HD bit barely cuts in a plain drill	It needs percussion; ITM says it will not cut with rotation only	Turn the hammer on, or switch to Cyclo Twist or slow spiral
Bit stops dead with a metal click	Rebar	Move the hole, or see rebar drill bits
Bit slows and squeals as the hole gets deep	Dust packed in the flutes	Pull the bit back every few seconds while it spins
Anchor spins or pulls out	Hole too big: worn tip, or the bit wobbled	Drill straight, and replace a bit with rounded carbide
Back face of the block blows out	Hammering hard as the bit breaks through	Ease off near the back, or drill from both sides
Bit spins in the chuck	Round shank under a big load	Tighten all three chuck holes, or use a hex-shank HD bit (5/8 in. and up)
Tile cracks over the block	Hammer on through tile	Drill the tile first with the hammer off; see how to drill through tile

Masonry drill bit questions

Is a masonry drill bit the same as a concrete drill bit?

Yes. Both names mean a carbide-tipped bit for brick, block, stone and concrete. What matters is whether the bit is made for the hammer setting.

Can I use a masonry bit on wood?

Yes, slowly. The carbide tip scrapes rather than slices, so the hole is rough and the bit runs hot. Use a wood bit when you have one.

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

Not the HD Roto Hammer: ITM says it will not perform with rotation only. A slow spiral or Cyclo Twist bit works in a regular drill.

What's the difference between a hammer drill and a rotary hammer?

A hammer drill makes light, fast blows with ribbed discs and takes straight-shank bits. A rotary hammer drives a piston, hits much harder, and takes SDS bits.

Can I use a masonry bit in an impact driver?

Not these. They have round or 3/8 in. and 1/2 in. hex shanks for a three-jaw chuck, not the 1/4 in. hex an impact driver takes.

Do I need water to drill concrete?

No. Carbide masonry bits drill dry. Clear the dust often, and wear eye protection and a dust mask, because concrete dust contains silica.

How do I know when a masonry bit is worn out?

The carbide corners round over and the anchor no longer grips. Measure the tip: once it is undersized, the hole is too.

Not sure which bit fits the drill and anchor you have? Call our team at (833) 4-ETOOLS or email sales@eldoradotools.com with the drill, the fastener and the wall, and we will name the bit.

Related: all masonry drills, SDS-Plus bits, types of drill bits, drill bit lengths and foundation repair tools.

Sources: ITM 2024 catalog, pp. 84–85 (Roto Percussion Drills, Standard and Heavy Duty); Tru-Cut Cyclo Twist product description; ITM stop bit labels for drop-in anchor sizes.

First published [date], with prices checked in our catalog on Nov 11, 2026.