SDS Max Extension and Adapter Guide: What Breaks Bits

What is an SDS Max extension, and what do you need to use one?

An SDS Max extension is a steel shaft that sits between the machine and the bit, so a short SDS-Max bit can drill deeper than its own length. It never works alone. The ITM X-Tendr system needs two parts: the X-Tendr adapter (XT6700) and one extension shaft.

The shaft's machine end locks into the SDS-Max chuck. The X-Tendr adapter has two locking SDS-Max inputs: one takes the shaft, the other takes the bit. ITM says the system works with any SDS-Max drill bit, core bit, tunnel bore drill, drill head or chisel. ITM lists the X-Tendr parts for use with SDS-Max impact drivers only.

Put the stack together in this order:

1. The SDS-Max impact driver.

2. One extension shaft: 12-1/2, 30, 44 or 82-1/2 in.

3. The XT6700 X-Tendr adapter.

4. Your SDS-Max bit, core bit or tunnel bore drill.

ITM limits the reach of the X-Tendr system to one adapter and one extension. Never stack two shafts to go deeper. Pick the one shaft that reaches.

Part	SKU	Length	Price	What it does
X-Tendr adapter	XT6700	7-1/2 in. long, 1-3/16 in. tall	$261.22 each	Joins the shaft to the bit; needed with every shaft
12-1/2 in. SDS-Max extension	XT6701	12-1/2 in.	$42.84 each	Short reach past a wall or slab
30 in. SDS-Max extension	XT6702	30 in.	$52.67 each	Most foundation and wall penetrations
44 in. SDS-Max extension	XT6703	44 in.	$71.89 each	Thick walls and footings
82-1/2 in. SDS-Max extension	XT6704	82-1/2 in.	$152.48 each	The only way past 47 in. in our catalog

Prices from eldoradotools.com on Oct 20, 2026. Each part is sold individually. Specs from ITM's product copy.

Our order history makes the point. Every order we have shipped with an X-Tendr adapter also had at least one extension shaft in it. Two orders had shafts and no adapter. A shaft without the adapter cannot hold a bit, so check that you own an XT6700 before you order a shaft alone.

Will the X-Tendr adapter fit through the hole?

The X-Tendr adapter passes through the hole only when the bit is 1-1/4 in. or larger, ITM says. The adapter is 1-3/16 in. tall, so a smaller hole stops it at the surface. With a bit under 1-1/4 in., the extension adds reach up to the adapter and no further.

That rule decides which holes an extension is good for:

• 1-1/4 in. and up: the adapter follows the bit into the wall, so the full shaft length counts. This is what the X-Tendr system is for.

• Under 1-1/4 in.: the adapter stays outside the hole. Buy a one-piece long bit instead. Our SDS-Max X-Cutter bits reach 31 in. from 5/8 in. up and 47 in. from 5/8 in. up.

Is an SDS Max extension cheaper than a long bit?

No, an SDS Max extension kit is not cheaper than a one-piece long bit for one hole size up to 47 in. deep. The XT6700 adapter alone is $261.22, more than half the cost of a kit. The kit pays off past 47 in., for core bits, or when one crew drills deep holes in several sizes and reuses the same adapter and shaft.

Job (1-1/2 in. hole unless noted)	X-Tendr kit	Kit total	One-piece bit	One-piece price
Through a 30 in. wall	XT6700 + XT6702 (30 in.) + SMTE1721 (1-1/2 x 12 x 17 in.)	$456.24	SMTE3621, 1-1/2 x 31 x 36 in.	$292.75
About 44 in. deep	XT6700 + XT6703 (44 in.) + SMTE1721	$475.46	SMTE5212, 1-1/2 x 47 x 52 in.	$429.93
Past 47 in.	XT6700 + XT6704 (82-1/2 in.) + SMTE1721	$556.05	None made	Kit only
2 in. core through a deep wall	XT6700 + XT6702 + 880SL1045 (2 x 22 in. core bit)	$553.60	None made	Kit only

Prices from eldoradotools.com on Oct 20, 2026, each sold individually. Drilling depth is the bit's own figure; check the reach of a kit against your wall before you drill.

The same comparison, trait by trait:

Trait	X-Tendr kit	One-piece long bit
Cost for one 1-1/2 in. hole size	$456.24 to $556.05 with the adapter	$292.75 (31 in.) or $429.93 (47 in.)
Deepest reach in our catalog	82-1/2 in. shaft	47 in. drilling depth
Smallest hole that takes the full reach	1-1/4 in. (the adapter must pass through)	5/8 in. at 31 in. and 47 in.
Core bits and tunnel bores	Yes, any SDS-Max core bit	No one-piece long core bits
Reuse across bit sizes	Yes, one adapter and shaft for every bit	No, one length per size
Joints in the stack	Two (shaft to adapter, adapter to bit)	None
Machine	SDS-Max impact drivers only (ITM)	Any SDS-Max hammer

Verdict: Buy a one-piece long bit for one hole size up to 47 in. Buy the X-Tendr adapter and one shaft to go past 47 in., to push a core bit deep, or to drill deep in several sizes.

Can you use SDS-Plus bits in an SDS-Max hammer?

Yes, an SDS-Max hammer can run SDS-Plus bits through an SDS Max to SDS Plus adapter. The ITM 725MAX001 ($75.16, sold individually) is an SDS-Max shank with an SDS-Plus chuck on the end. It keeps one machine on the job for big and small holes, for example a run of anchors overhead.

The adapter has three rules. They are ours and ITM's; no maker prints a size limit.

1. Keep to small bits. An SDS-Max hammer hits far harder than an SDS-Plus bit is built for. We keep the adapter to 5/8 in. and under and switch to a true SDS-Max bit above that.

2. Expect faster wear. Even a small SDS-Plus bit wears quicker under SDS-Max impact energy.

3. Never chisel through it. The adapter adds a joint. In hammer-only mode that joint eats energy and works loose.

Job through the 725MAX001	Bit	Price	Minimum order
1/2 in. anchor holes	715S63264, 1/2 in. SDS-Plus Bohr Hammer bit	$7.21 each	5
1/2 in. holes with rebar in the slab	EVL63264, 1/2 in. SDS-Plus X-Cutter	$12.56 each	4
Drop-in anchors overhead	STP-813, SDS-Plus stop bit	$18.62 each	2
Daily 1/2 in. slab holes (skip the adapter)	SMTE1312, 1/2 x 8 x 13 in. SDS-Max X-Cutter	$41.99 each	1

Prices from eldoradotools.com on Oct 20, 2026; minimums from our product data.

For the full shank comparison, see SDS-Plus vs SDS-Max: which shank for the job.

Is there an SDS Plus to SDS Max adapter?

No, there is no SDS Plus to SDS Max adapter we would sell or recommend. A few listings claim to put an SDS-Max bit in an SDS-Plus hammer, but most products sold under that name go the other way. An SDS-Plus hammer cannot deliver the energy an SDS-Max bit needs. Hammering a big bit through a small chuck strains the hammer and the adapter.

If the job needs an SDS-Max bit, it needs an SDS-Max machine. Check the direction on any adapter before you buy: the machine end must match your hammer, and the bit end must match your bits.

How do tapered extensions drive a core drill?

A tapered extension drives an ITM taper-fit carbide core drill from an SDS-Max machine, with a pilot drill in the middle. The 720MAX008 (8 in., $71.24) and 720MAX018 (18 in., $95.75) fit core drills such as the 719CB0050 (2 in., $129.26). The 721PD0385 pilot drill ($11.86 each, minimum 5) goes through the extension.

ITM's steps for coring with a tapered extension:

1. Clean both tapers.

2. Put the pilot drill in the extension, then seat the extension in the core drill.

3. Drill about 3/8 in. deep, then take the pilot out.

4. Core until the core drill is full, about 3 in.

5. Break out the core with a chisel and repeat to depth.

ITM warns that running without the pilot drill can break the extension between its two slots.

What breaks bits on an SDS-Max adapter or extension?

Most broken bits on an adapter or extension come from using it for a job it was not made for. The table lists what we see and the fix.

Problem	Likely cause	Fix
SDS-Plus bit snaps at the 725MAX001	Bit over 5/8 in., or side load	Keep to 5/8 in. and under; use a true SDS-Max bit above that
SDS-Plus chisel breaks or the adapter works loose	Chiseling through the 725MAX001	Never chisel through an adapter; use an SDS-Max chisel
Extension stops short of the far side	Bit under 1-1/4 in., so the X-Tendr adapter cannot follow	Use a one-piece long bit for holes under 1-1/4 in.
Joint loosens or bit wobbles deep in the hole	Two shafts stacked	One adapter and one shaft only (ITM); pick the longer shaft
Tapered extension cracks between the slots	No pilot drill	Always run the 721PD0385 pilot first
Bit shank wears fast or heats up	Dry, dirty shanks	Clean and grease every shank before it goes in
Bit binds or snaps in a deep hole	Leaning on the machine, or dust packing the hole	Keep the stack straight; pull back often to clear dust

For drilling through rebar in footings, see our rebar drill bit guide. For the full foundation kit, see foundation repair tools.

FAQ

Do they make an SDS extension?

Yes. For SDS-Max, the ITM X-Tendr system has shafts of 12-1/2, 30, 44 and 82-1/2 in., used with the XT6700 adapter. Browse them in SDS-Max extensions and adaptors.

What is an SDS adapter?

An SDS adapter changes one shank system to another. The common one, like the ITM 725MAX001, lets an SDS-Max hammer take SDS-Plus bits.

Is SDS-Max compatible with SDS-Plus?

No. SDS-Max is an 18 mm shank and SDS-Plus is 10 mm, so the bits do not interchange. An adapter lets an SDS-Max hammer run small SDS-Plus bits, not the reverse.

Can you convert SDS-Plus to SDS-Max?

Not in a way we recommend. An SDS-Plus hammer is too light for SDS-Max bits. Use an SDS-Max machine for SDS-Max bits.

Does an SDS Max extension fit any machine?

No. ITM lists the X-Tendr parts for use with SDS-Max impact drivers only.

Is the X-Tendr like Milwaukee MAX-LOK or Hilti TE-FY?

They do the same job: a coupler plus an extension shaft for SDS-Max bits. Keep to one system's parts in a stack; we stock and support X-Tendr. The ITM X-Tendr adapter is $261.22 and its shafts run $42.84 to $152.48.

Where can I buy an SDS Max extension?

We sell every X-Tendr part individually, with no minimum. The 30 in. XT6702 is $52.67.

Not sure which length or bit fits your wall? Call our team at (833) 4-ETOOLS or email sales@eldoradotools.com.

Sources: X-Tendr, tapered extension and adapter specs and instructions from ITM's product copy; prices and minimums from eldoradotools.com and our product data on Oct 20, 2026; order patterns from our own order history (June 2024 to October 2026).

Change log: first drafted Oct 20, 2026, with prices checked that day.