ISO 5608 Designation · ISO 5610 Shanks · Blanks and Custom

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Tool Holders and Boring Bars for Indexable Inserts

Indexable tool holders, turning tool holders and boring bars that put the insert where the drawing needs it. External turning holders for the main ISO insert families, mill boring bars for internal work, and tool holder blanks for shops that grind their own forms — matched shank sections, clamping type and coolant path, quoted with the inserts that fit. Send the insert code or the holder you replace and we match the interface.

External turning holders, boring bars and milling holders
Matched to CNMG, DNMG, VNMG, WNMG, CCMT and TCMT insert codes
Lever, wedge and screw clamping types
Square and rectangular shanks to ISO 5610; tool holder blanks
Coolant-through holders where the setup needs it

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Quotes within hours — email or WhatsAppWorldwide shipping from Guangzhou, China

What a tool holder does: positioning, clamping and rigidity

A tool holder is the interface between the cutting edge and the machine: it holds the insert at the angle the operation needs, takes the cutting force into the machine structure, and defines how far the edge can reach without deflecting. Two holders that carry the same insert can behave completely differently — one is rigid and repeats, the other flexes and chatters — and the difference is in the shank, the clamping and the overhang rather than in the insert.

That is why a holder is chosen backwards from the insert and the machine: the insert code fixes the pocket (shape letter, IC size and thickness all have to match), the machine fixes the interface — a square shank for the tool post, a round bar for a bore, an arbor or shell mount for a mill — and the operation fixes the clamping and the coolant path. Get those three right and the insert performs to its grade; get any one wrong and no grade will save the surface finish.

Turning holders and cartridges with rectangular shanks are designated under ISO 5608, with the standard dimensional series for rectangular-shank holders in the ISO 5610 family — the shank section and tool length are encoded in the reference, which is why a holder is quoted by its full code rather than by a picture. Beyond turning, boring bars, milling cutter bodies and modular couplings carry the same logic into the bore and onto the spindle.

Reading a holder reference

Insert shape letter — C, D, S, T, V, W: which shape group the pocket takes.
Shank code — 1212, 1616, 2020, 2525: shank height and width in mm.
Tool length code — a letter for the usable length of the holder.
Hand — right or left hand, which decides the cutting direction.
Clamping — lever, wedge or screw, the company-specific part of the code.

Tool Holder Types

Turning holders, boring bars and milling holders

External turning tool holders

The classic rectangular-shank holder that carries a clamped insert up to the outside diameter of the workpiece. Shank sections are encoded in the part number — 1212, 1616, 2020 and 2525 — and the insert pocket is what decides which insert code fits: a DNMG holder takes a 55° rhombic insert with a given IC and thickness, not a similar-looking one from another shape group.

Boring bars for internal turning

A boring bar is a holder that reaches inside the bore: round shank, insert at the end, and — above all — a length-to-diameter ratio that decides how much it will deflect. Keep the overhang as short as the feature allows, choose the largest bar that fits the bore, and prefer a bar with internal coolant on deep bores where chips need help leaving.

Milling holders and cutter bodies

On the milling side the same logic applies with a different interface: a cutter body carries the insert and the machine spindle carries the body through an arbor, a shell mount or a collet chuck. Body, arbor and insert pockets are quoted as one set, because a pocket mismatch cannot be corrected with a different insert.

Around those three families sit the pieces that make a setup work: boring bar extensions, tool post and turret adaptors, spare clamp screws and keys, and the holder blanks that let a shop grind its own seat. They are quoted alongside the holder rather than as separate catalogue lines, so one order fits the machine.

Technical Specifications

Tool Holder Selection Guide — Insert Fitting, Shank, Clamping and Rigidity

Match the Insert Code First

CNMG, DNMG, WNMG, CCMT, TCMT — pocket decides

A holder is defined by the insert it clamps: shape letter, IC size and thickness must match the pocket. Send the code you run now, or the holder reference, and the fit is confirmed before the order.

Shank and Machine Interface

Square shanks, round bars, arbor and shell mounts

Turning holders are designated by shank section (1212 to 2525 in the common range), boring bars by diameter and length, and milling bodies by arbor, shell or taper interface — all of which must match the machine before the insert matters.

Clamping, Rigidity and Coolant

Lever, wedge and screw clamping; internal coolant

Clamping type sets how fast the insert changes and how much the edge can move under load; overhang ratio sets how much the bar deflects; coolant ports decide whether chips leave the cut. Those three decide the result.

Parameter	Technical Details / Standard Values
Matching the holder to the insert	The insert pocket fixes the shape letter and the IC size: a DNMG insert needs a D-shape pocket of the matching IC and thickness, and a CCMT needs a C-shape positive pocket. Same-looking inserts across shape groups are not interchangeable — check the code on both the insert and the holder before quoting, and we confirm the pairing from the reference numbers.
Shank and interface	Rectangular shanks are quoted by section — 1212, 1616, 2020 and 2525 are the common square sizes, with the height and width encoded in the holder designation to ISO 5608 — round boring bars by diameter and length, and milling bodies by their spindle interface. The shank has to sit in the tool post or turret the machine actually has.
Clamping method	Lever clamping locks the insert from a central hole and holds it securely with a fast index change; wedge clamping presses the insert into a V-seat for maximum rigidity on heavy cuts; screw clamping is compact and the first choice where the pocket is small or the geometry unusual. Each has a place — the heavier and more interrupted the cut, the more the fixture matters.
Cooling path	A holder with internal coolant delivers fluid to the insert edge rather than over the top of the cut, which is what deep bores and long overhangs need. Where the machine has no through-coolant supply, the same holder can be run external — but the chip evacuation plan has to change with it.
Rigidity and overhang ratio	Deflection rises sharply with overhang: a boring bar at four times its diameter behaves very differently from the same bar at two. Choose the shortest and largest bar the bore allows, reduce the depth of cut before reducing the feed, and treat chatter as a setup problem rather than a grade problem.
Blanks and custom holders	Tool holder blanks let a shop grind its own seat for a form or a special insert geometry, and custom holders are made to a drawing where no stock interface fits. Both are quoted against the drawing, with the insert or the seat geometry confirmed before production.

Running a holder that is not in the catalogue, or need a blank ground for a special seat? Send the insert code, the machine interface and the drawing — holders, blanks and the matching inserts can be quoted as one set.

Holder Families & Interfaces

Holder families, shank sections and the inserts they take

Holder family	Shank & interface	Matching insert code	Typical application
External turning holders	Square shank 1212 / 1616 / 2020 / 2525; ISO 5608 designation	CNMG, DNMG, VNMG, WNMG, CCMT, TCMT	Outside diameter, facing and profiling in the lathe
Boring bars	Round shank by diameter and length; internal coolant option	CCMT, DCMT, TCMT and matching negative forms	Internal turning and boring, shortest overhang possible
Milling holders and bodies	Arbor, shell mount or collet interface to the spindle	Square, round and shoulder milling insert families	Facing, shoulder and slotting work on CNC mills
Threading and grooving holders	Rectangular shank, laydown insert seat	16ER / 22ER threading and grooving insert forms	Thread turning and grooving with the insert seated low
Tool holder blanks	Unmachined or part-machined shank to drawing	Seat ground by the shop for special geometries	Custom and repair work where no stock pocket fits
Modular interfaces	Coupling between the machine and the cutting unit	Any matched cutting unit for the application	Quick change and long reach where rigidity allows

Shank sections are shown in the common square range; ISO 5608 governs the holder designation code and the ISO 5610 series the rectangular-shank dimensions. Blanks and custom holders are quoted to drawing.

A holder reference is read like the insert code it carries: the shape letter tells you which insert family the pocket accepts, the four-digit shank code gives the height and width in millimetres (1616 is a 16 mm square shank), the length letter gives the usable reach, and the hand decides which direction the tool cuts. That is how a turning tool holder is quoted without ambiguity — and why replacing a holder starts with the code on the old one, not the photo of it.

Related reference pages

Why Buyers Work With InsertCore

Sourcing, verification and support around your tooling setup

Holder, pocket and insert matched before shipping

Holders are quoted against the insert code or the reference of the holder being replaced, and the pocket, shank section and clamping are confirmed against the quotation. Dimensional reports are available on request.

Blanks and custom holders

Tool holder blanks, special seats and holders made to a drawing are quoted with the insert that will sit in them — including trial pieces before a production order.

Sourced and QC-verified supply, one contact

We are a trading operation, not a production plant: holders are sourced from vetted tooling partners and checked before dispatch, and the same contact stays with your programme from quote to delivery.

Quote turnaround

Within hours

Channels

Email + WhatsApp

Shipping

Worldwide, tracked

Quantities

Trial to bulk

Questions Buyers Ask

Holder fitting, clamping and rigidity questions, answered

How do I choose a tool holder for my insert?

Start from the insert code, not the holder: the shape letter and the IC size decide the pocket (a DNMG insert needs a D-shape pocket of the matching IC and thickness), then the shank section has to match the tool post or turret, and the clamping type follows the cut. If the machine setup is tight or the overhang long, choose the boring bar diameter before anything else — the holder that deflects is the holder that fails.

How much overhang can a boring bar take?

As little as the feature allows. Deflection grows steeply with length-to-diameter ratio, so a bar at two times diameter is rigid where the same bar at four times is not: keep the overhang short, choose the largest bar that enters the bore, and reduce depth of cut before reducing feed. Chatter in a bore is almost always a setup answer — shorter overhang, bigger bar, tighter clamping — not a different insert grade.

Lever, wedge or screw clamping — what is the difference?

Lever clamping locks through the insert hole and gives the fastest index change with good rigidity, which is why it dominates general turning. Wedge clamping presses the insert into a V-seat and is the most rigid on heavy and interrupted cuts. Screw clamping is compact and suits small or unusual pockets. All three are in use for good reasons — match the fixture to the load, then to the changeover time you can accept.

Can I buy tool holder blanks and grind my own seat?

Yes. Tool holder blanks are supplied unmachined or part-machined for shops that grind a special seat for a form insert or a repair job, and they are quoted to the drawing with the seat geometry confirmed beforehand. For anything outside the stock interfaces, a holder made to a drawing is usually the faster route than adapting a standard one.

Do I need a holder with internal coolant?

Where the cut is deep, the material is gummy or the bar is long, yes: internal coolant puts fluid at the insert edge and drives the chip out of the bore instead of letting it recirculate. For short, open cuts external coolant is usually enough. If the machine has no through-coolant supply, plan the chip evacuation differently rather than buying the port and not using it.

When is a modular tool holder the right choice?

When changeover time or reach decides the job: a modular coupling lets one machine carry several cutting units and swap them in seconds, and it extends reach where a solid bar would deflect. The trade is a joint in the load path — so modular pays in flexible, mixed-batch production, and a solid holder stays the first choice for the heaviest cuts.

How do you control tool holder quality?

Holders are sourced from vetted tooling partners and inspected before dispatch. Pocket geometry, shank section, clamping and interface are confirmed against the quotation, dimensional reports are supplied on request, and each shipment is packed for transit. If a holder does not fit as confirmed, send the reference, the insert code and your measurements and we will put it right.

What information should I send for an accurate tool holder quote?

The insert code you run (or the holder reference being replaced), the machine and tool post or turret interface, the operation and whether the cut is interrupted, the overhang or bore depth, and the quantity. With those points we confirm the pocket, the shank and the clamping instead of shipping a near-match that needs the seat modified.

How fast can I get pricing, and how are orders shipped?

Quotations are normally issued within hours during business hours — email and WhatsApp reach us directly. Orders ship worldwide from Guangzhou, China with tracking, and payment terms are stated on the quotation. Holders are usually ordered with their inserts; trial quantities and mixed-item orders are both welcome.

Get your tool holder quote within hours

Send the insert code, the machine interface and the overhang you need — you get the holder, clamping type and coolant option matched to it, with the inserts that fit.

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