Boring Bars

Boring bars for CNC lathes: solid carbide mini bars, 3/8" and 1/2", for small bores; damped anti-vibration bars, 20 mm to 2", for deep ones. Prices online, no quote needed.

Pick the shortest bar that clears the depth and the largest shank the hole allows. Steel chatters past 4×D, carbide holds further, a damped bar reaches 7–10×D.

Every bar needs a holder and an insert; anti-vibration bars also need a boring head, sold separately.

Solid Carbide Anti-Vibration 2" Dia. 10xD Overhang Boring Bar Heads →

Total found: 4

Only new

Only in stock

Holder Style: Solid Carbide

3/8" Dia. Mini Solid Carbide Boring Bar, CCMT 21.5, Right Hand

CA$294.86 excl. taxes

E06H-SCLCR-22 unit in stock

3/8" Dia. Mini Solid Carbide Boring Bar, CCMT 21.5, Right Hand

3/8" Dia. Mini Solid Carbide Boring Bar, DCMT 21.5, Right Hand

CA$308.86 excl. taxes

E06H-SDUCR-22 unit in stock

3/8" Dia. Mini Solid Carbide Boring Bar, DCMT 21.5, Right Hand

CA$420.43 excl. taxes

E08K-SCLCR-22 unit in stock

1/2" Dia. Mini Solid Carbide Boring Bar, CCMT 21.5, Right Hand

1/2" Dia. Mini Solid Carbide Boring Bar, DCMT 21.5, Right Hand

CA$422.58 excl. taxes

E08K-SDUCR-22 unit in stock

1/2" Dia. Mini Solid Carbide Boring Bar, DCMT 21.5, Right Hand

Why a boring bar chatters, and how far it can reach

A lathe boring bar is a cantilever: clamped at one end, cutting at the other. Its deflection grows with the cube of the overhang and falls with the fourth power of the diameter. Double the stick-out and the tip moves eight times as far under the same cutting force. Go from a 1/2" to a 5/8" shank and the bar gets about 2.4 times stiffer. That is why the overhang ratio — stick-out divided by shank diameter, written as 4xD, 7xD, 10xD — tells you more about a boring job than the bore size does.

Once the bar deflects, it starts to vibrate. Chatter marks in the bore, a squeal, an insert that chips after a few parts and a bore that comes out tapered are all the same problem. The usual limits:

Steel bar — about 4xD before chatter sets in.
Solid carbide bar — about 6xD. Carbide is roughly three times stiffer than steel.
Anti-vibration (damped) bar — 7xD to 10xD, cutting at normal speeds and feeds.

Slowing down, cutting the feed and grinding a sharper insert all buy a little more reach. Past a point they only trade chatter for cycle time, and the right answer is a different bar.

Anti-vibration boring bars

An anti-vibration boring bar carries a heavy damping mass inside its body. When the bar starts to vibrate, the mass moves against it and absorbs the energy before the vibration can build up at the insert. The bar still bends under the cutting load like any other, but it stops ringing — and ringing is what ruins the surface and the insert.

We run these bars in our own machine shop, Volk CNC, on deep bores that a solid bar would not finish. In theory a damped bar is a compromise: the body is hollowed out for the damper, so it is a little less stiff than a solid bar of the same size. In practice that never shows up in the part. What limits the cut is the overhang, the insert and the clamping, not the damper.

All our anti-vibration bars have through-coolant to the head:

2" — 7xD (14" of reach) and 10xD (20").
1" — 10xD, 10" of reach.
32 mm (1.26") — 10xD, 12.6" of reach, with a 2" sleeve included.
20 mm (0.787") — 10xD, 7.9" of reach, carbide front section.

7xD or 10xD. Take the shorter bar whenever the bore allows it. A 2" 7xD bar reaches 14" deep, weighs less, is easier to fit on the turret and costs noticeably less than the 10xD version. Go to 10xD only for bores deeper than that.

The boring head is ordered separately

Anti-vibration bars come without a cutting head. The head screws onto the front of the bar, carries the insert and sets the minimum bore. One bar can therefore take a negative DNMG head for roughing, a positive DCMT head for finishing and a back boring head that cuts on the way out. The coupling size on the head has to match the bar:

40 mm heads — for the 2" bars and every bar from 40 mm up. Minimum bore on a 2" bar is 2.362" (60 mm), 2.480" (63 mm) with the VNMG head. The coupling is off-centre on bars larger than 40 mm, so the insert still reaches past the bar diameter.
32 mm heads — for the 32 mm bar, bores from 1.575" (40 mm).
25 mm heads — for the 1" bar, bores from 1.181" (30 mm), 1.260" (32 mm) for back boring.
20 mm heads — for the 20 mm bar, bores from 0.945" (24 mm).

The boring bar heads take standard DNMG, VNMG, CCMT and DCMT inserts, so one insert stock covers your OD tools and your boring bars.

Inch holder, metric bar

The 1" and 2" bars are inch sizes and clamp straight into an inch boring bar holder. The others are metric. A metric bar never replaces an inch one on its own, because the nearest metric size is often slightly larger than the hole in the holder — a 40 mm bar does not enter a 1-1/2" bore. The fix is a smaller metric bar with a reducing sleeve. That is why the 32 mm bar ships with a 2" sleeve: it clamps in a standard 2" holder with no changes.

Solid carbide mini boring bars

For small holes, solid carbide mini boring bars with 3/8" and 1/2" shanks. Each bar has a ground clamping flat and a Torx screw, and takes CCMT 21.5 or DCMT 21.5 inserts. CCGT inserts of the same size fit too and are the better choice for aluminum.

3/8" bars — bores from 0.433" (CCMT, 95° lead) and 0.610" (DCMT, 93°).
1/2" bars — bores from 0.512" (CCMT) and 0.728" (DCMT).

The CCMT bar is the stronger one for general boring. The DCMT bar, with its 55° insert, reaches into corners and profiles. Coolant is external. Because carbide is so much stiffer than steel, a small carbide boring bar holds size at stick-outs where a steel bar of the same diameter would already chatter.

How to choose a boring bar

Two rules come first: use the shortest bar that clears the depth, and the largest shank the hole allows. Then go by the smallest bore and the depth:

Smallest bore	Bar	Deepest reach
0.433"–0.728"	3/8" or 1/2" solid carbide mini bar	short bores, about 6xD
from 0.945" (24 mm)	20 mm anti-vibration, 10xD	7.9"
from 1.181" (30 mm)	1" anti-vibration, 10xD	10"
from 1.575" (40 mm)	32 mm anti-vibration, 10xD, in a 2" sleeve	12.6"
from 2.362" (60 mm)	2" anti-vibration, 7xD or 10xD	14" or 20"

If the bore is large and shallow, a damped bar is not needed. A larger bar at a short overhang will be stiff enough on its own.

What else you need

A boring bar for a lathe works only as part of a set:

A boring bar holder for your turret, BMT or VDI, with a bore that matches the bar shank.
Turning inserts for the bar or the head.
For anti-vibration bars, a boring head with the matching coupling size.

Buying boring bars from CNCmarket

Every EASYCUT indexable boring bar and boring head has its price on the product page. Order online at any time, with no quote and no waiting for a sales rep, and we ship anywhere in Canada. If you need a diameter or overhang that is not listed, or are unsure which bar fits your bore and your turret, send us the bore size, depth and machine and we will tell you what to use.

Boring Bars

Why a boring bar chatters, and how far it can reach

Anti-vibration boring bars

The boring head is ordered separately

Inch holder, metric bar

Solid carbide mini boring bars

How to choose a boring bar

What else you need

Buying boring bars from CNCmarket

Frequently Asked Questions

Why a boring bar chatters, and how far it can reach

Anti-vibration boring bars

The boring head is ordered separately

Inch holder, metric bar

Solid carbide mini boring bars

How to choose a boring bar

What else you need

Buying boring bars from CNCmarket

Frequently Asked Questions