Turning, milling, cross-drilling, tapping and back-face work completed in a single setup on 18 B-axis multitasking centres. Ø5–150 mm, feature-to-feature position held to 0.010 mm, and an engineer reviewing every drawing before it is priced.
CNC mill-turn machining — also called turn-mill or multitasking machining — performs turning and milling operations on one machine against a single workholding. The main spindle rotates the part for turning, then indexes and locks angular position so driven tools can mill flats, cut slots and drill cross-holes. A sub-spindle receives the part for back-face work under machine control, so a two-sided component with milled features finishes complete in one cycle.
Four machine elements make that possible, and it is worth knowing them by name because they appear in every capability list you will compare:
The C-axis turns the main spindle into a precision rotary axis. Instead of only spinning, it can be positioned to a specific angle and held there under cutting load, which is what allows a cross-hole to be drilled at 47° from the same origin the outside diameter was turned against.
Live tooling — also called driven tooling — puts powered rotating cutters in the turret so milling, drilling and tapping happen without moving the part to a machining centre.
The Y-axis allows the tool to move off the spindle centreline, which is what makes an off-centre pocket, a flat or a hex possible rather than only features that intersect the axis.
The B-axis tilts the entire milling head so the tool can approach the workpiece at any angle. This is the element that separates a full multitasking centre from a lathe with live tooling, and it is what allows a compound-angle port or an angled boss to be cut without a fixture built specifically to present that face.
The process is sometimes described as done-in-one machining. That is the goal rather than a guarantee — a part that needs grinding after heat treatment still needs grinding. But for the large class of components that are fundamentally a turned body carrying milled features, one clamp genuinely replaces an entire multi-machine route.
The term covers everything from a lathe with a few driven tools to a full multitasking centre with a tilting head. The difference decides whether your part runs in one setup or three, so it is worth confirming before you compare two quotes against each other.
A CNC lathe with driven tools and an indexing spindle.
Adds off-centre milling and a second spindle for back-face work.
A tilting milling head positioned at any angle, with simultaneous interpolation.
If your drawing has any feature that is not perpendicular or parallel to the turning axis, say so explicitly in your enquiry. That single line decides which of the three machine types can hold your print, and it is the most common reason a mill-turn quote and a conventional quote are not comparing the same work.
Four advantages carry real weight on a quote. The first is the one most often claimed and least often quantified, so we have put numbers against it below.
Every time a part is unclamped and re-fixtured, its datum is rebuilt from a new reference surface. The error that enters at that moment cannot be inspected back out — it is already in the part. Concentricity between a front bore and a rear seat, or true position of a cross-hole relative to a back-face datum, is the sum of every clamping error along the route.
In a single setup those relationships never cross a clamp. We hold feature-to-feature position to 0.010 mm, governed by machine geometry rather than by how well someone re-seated the part.
A milled feature on a turned body usually needs a dedicated fixture — designed, made, proved, stored and maintained for one part number. Across 20,000 pieces a year that cost vanishes into the unit price. Across 400 pieces in two releases, it is most of what you are paying for.
A B-axis head reaches the feature from the turning datum, so the fixture is never made. This is why mid-volume programmes with tight prints often quote lower on the more expensive machine.
A five-operation part rarely spends five operations’ worth of time being machined. It waits — in front of the second lathe, in front of the mill, at the deburr bench, at each inspection gate. Trimming 20% off cycle time changes little when most of the calendar is queue.
Collapsing five operations to one removes four queues, four material moves and three inspection gates, which is why production here runs 15–20 working days rather than the multi-month quotes common on multi-operation routes.
Each transfer between operations is a chance to drop, scratch or mis-load a component. On soft materials, plated surfaces and thin-walled parts, handling damage is a meaningful share of scrap. Single-setup machining removes those touches from the route entirely.
Select every operation your part needs today
Stack figures use ±0.03 mm re-fixture uncertainty per setup as a planning estimate. Your real number depends on fixture design, part rigidity and datum scheme, which is why an engineer reviews every drawing before we price it.
Check your largest turned diameter and overall length against the envelope below. Every figure is given in metric and imperial because drawings arrive in both.
| Machine | Configuration | Units | Diameter |
|---|---|---|---|
| Mazak Integrex-class | Main and sub-spindle, B-axis milling head, lower turret | 18 | Ø8 – 150 mm |
| Mazak CNC lathes, live tooling | Main spindle, C-axis, driven tools | 36 | Ø8 – 150 mm |
| Citizen BNC 40# | Fixed headstock turn-mill with sub-spindle | 4 | Ø5 – 120 mm |
| Yangmu LM-06Y 46# | Fixed headstock turn-mill with Y-axis | 2 | Ø5 – 150 mm |
| Mazak VARIAXIS C-600 | Simultaneous 5-axis, for features beyond the turn-mill envelope | 1 | — |
Single-setup machining means the part sits in one grip for the whole cycle, so what matters shifts — less about how fast a material cuts, more about how it moves while it is being held. These are grades we run in production, grouped by the behaviour that drives the process plan.
Aluminium 6061-T6 · 6082-T651 · 7075-T6 · 2024-T351 · brass C3604 · C36000 · copper C11000 · C14500
High thermal conductivity means the part takes on spindle and cutting heat quickly and releases it slowly. On a Ø80 mm bore held to ±0.01 mm, growth across a long cycle is not noise — it is most of the tolerance band. We schedule finishing passes late and allow the part to stabilise, but if a bore is that critical, say so and we plan the cycle around it rather than discovering the drift at first article.
Stainless 304 · 304L · 316 · 316L · 17-4 PH · 440C · Inconel 718 · 625 · Monel 400 · Hastelloy C276
These work-harden under a dwelling or worn tool, so a re-cut across a previously touched surface fights a harder skin than the first pass did. Consolidation helps in a way that is easy to overlook: fewer passes over the same surface, no re-entry after a part has sat for a day, and no chance of a second machine cutting into a hardened layer someone else created.
Ti-6Al-4V Gr 5 · Ti-6Al-4V ELI Gr 23 · CP Gr 2 · 4140 · 4340 · 16MnCr5 · thin-walled parts in any alloy
Residual stress relaxes when clamping pressure comes off and when material is removed asymmetrically. Every re-clamp on a stressed part is a chance for it to settle into a different shape than the one that was inspected. One clamp does not eliminate stress, but it removes the release-and-regrip events where that stress usually expresses itself.
PEEK · PTFE · POM · Nylon 66 · PEI · thin-wall bronze and copper
Soft and low-modulus materials take a shape from the chuck and give it back after release, so a bore measured in the machine is not the bore you receive. We use lower clamping pressure over more contact area, and single-setup work means that compromise is struck once rather than at every operation.
Mill-turned components tend to share one profile: a turned body carrying features that are not turned. These are the sectors where that profile is most common, with the parts we actually produce.
Diaphragm valve bodies, BA-grade VCR fittings, pressure-reducing valve components, ultra-high-pressure tube fittings and gas stick hardware. Machined, honed and electropolished in house.
Hydraulic and pneumatic valve bodies, cartridge valve cavities, manifold blocks with cross-drilled intersections, cylinder end caps, gland nuts and piston rods.
Sensor housings, ABS and hydraulic valve components, transmission and driveline parts, EV charging hardware, turbocharger components and precision fasteners.
Hydraulic fittings, control system components, bushings and bearing housings, connector shells and specialty fasteners in titanium, Inconel and 17-4 PH.
Surgical instrument bodies, handpiece components, dental abutment parts and diagnostic equipment hardware. Implantable device work is subject to scope review before we quote.
Gearbox housings, output shafts and flanges, end-effector bodies, linear actuator components and precision spacers. Existing production for a Korean industrial robotics OEM.
Six notes we send back to engineers most often. Handling them at the drawing stage is free; handling them at first article is not.
Mill-turn earns its value by holding one datum through every operation. If half the features are dimensioned from the OD and half from a back-face bore, someone has to choose which relationship to protect. Tell us which one the part fails on and the operation sequence is built around it.
An angled port, a boss on a taper or a hole that is not radial decides whether your part needs a B-axis head or a fixtured milling operation. It is one line on the enquiry and it changes the quote more than almost anything else on the print.
The part has to be held somewhere while it is machined everywhere else. A short body with features running to both ends may need a sacrificial gripping allowance parted off at the end, or a soft-jaw step designed into the blank. Adding 6–8 mm of stock is usually cheaper than a bespoke fixture.
A twenty-minute cycle heats both part and spindle. On a large bore held to ±0.01 mm that growth consumes most of the tolerance band. We schedule finishing passes accordingly, but flagging the critical bore lets us plan the cycle rather than react to the drift.
Deep bores, blind cross-holes and internal cavities trap chips, and a trapped chip during a twenty-tool cycle scraps the part rather than the pass. Through-coolant access, a chip relief groove or a modest change in hole intersection angle removes that risk at no functional cost.
A drawing with ±0.01 mm on everything is priced as though everything is critical. Mark the two or three features that carry function and open up the rest. You usually get a better price and a better part, because inspection effort concentrates where it changes something.
A turn-mill centre carries a higher hourly rate than a lathe and a machining centre considered separately, and programming takes longer because one program has to sequence twenty tools, a spindle handoff and a full back-face operation. Both costs land on every job.
They are repaid by what disappears: two machine queues, one or more fixtures, several setups, the inspection gates between them, and the work-in-process sitting in the middle. Where the part is simple there is nothing to repay them with.
The break usually falls on feature count and tolerance rather than on volume. Below about three operations, or where every feature-to-feature relationship is open, a conventional route is cheaper at any quantity. Above six operations, or wherever a print carries a tight positional or concentricity callout across faces, mill-turn is often cheaper even at fifty pieces — because the alternative needs a fixture, and sometimes a grinding operation, to hold what one clamp holds for free.
A turned bushing with two radial holes and open tolerances gains nothing from a B-axis head. Parts like this belong on our CNC lathes and we move them there without being asked.
For form, roundness and finish beyond Ra 0.4 µm on a bearing surface, or any diameter finished after heat treatment, grinding is still the answer. We run centreless and cylindrical grinding in the same plant, but it is a separate operation and the quote shows it as one.
Compound-angle interpolation has to be simulated before it is proved on metal. That time is quoted up front rather than absorbed quietly into a longer schedule.
When a part is 90% finished and a trapped chip damages a bore, you lose the whole cycle rather than one operation — which is why chip evacuation is discussed at design review rather than after.
Past roughly 4:1 length to diameter a chucked part deflects away from the tool regardless of machine quality. Those parts want a guide bushing — see our Swiss CNC machining cells for Ø0.5–25 mm slender work.
A part machined in one setup has to be inspected differently from one machined in five. The claim being made is about relationships between features, so that is what the report has to demonstrate.
First article inspection runs on a Mitutoyo 4078M-1211 CMM against the datum scheme on your drawing — true position, concentricity, runout and perpendicularity, rather than a list of independent dimensions. On compound-angle features this is the only practical method, because an optical comparator cannot present the feature squarely to be measured.
In production, the features that drift are checked on a schedule: tool wear across a twenty-tool cycle is predictable behaviour, planned for rather than discovered. Where a programme runs high volume, critical diameters and lengths also pass through automated optical sorting on our six CCD inspection machines, so the lot carries a defect rate you can defend to your own customer rather than infer from a sample.
CMM to ±0.001 mm, three vision measuring systems, 2.5D measuring, four optical comparators, six CCD sorting machines to ±0.002 mm, surface roughness, hardness, salt spray and XRF for RoHS.
Material certificates traceable to the mill, dimensional reports including geometric callouts, FAI packages in AS9102 format, PPAP to your required level, RoHS and REACH declarations, plating and heat-treatment certificates.
IATF 16949:2016, AS9100D, ISO 14001:2015 and ISO 10012 measurement management — the last governing how our gauges themselves are controlled. Records retained three years, traceable to lot and machine. Customer audits welcome.
Finishing continues under the same control plan: centreless and cylindrical grinding, honing and abrasive flow for cross-hole intersections, electron beam welding, electropolishing for ultra-high-purity work, and passivation and anodising in house. Plating and heat treatment run on qualified partner lines, with our incoming inspection applied when parts return. ISO 13485 is not currently held, so implantable medical device work is subject to scope review before we quote.
Four processes overlap around small precision components. This is how we route parts internally, and how we would advise you if the part arrived without a process specified.
| Mill-Turn | CNC Turning | Swiss-Type | 5-Axis Milling | |
|---|---|---|---|---|
| Part character | Turned body with milled features | Mostly rotational | Long, slender, small | Prismatic, contoured |
| Diameter range | Ø5 – 150 mm | Ø8 – 150 mm | Ø0.5 – 25 mm | Not applicable |
| Typical setups | 1 | 2 – 3 | 1 | 1 – 2 |
| Compound angles | Yes, B-axis head | No | Limited | Yes |
| Back-face work | Sub-spindle transfer | Second operation | Sub-spindle transfer | Re-fixture |
| Setup cost | Medium to high | Low | High | Medium |
| Cycle cost | Medium | Medium | Very low | High |
| Economic quantity | 50 – 10,000 | 50 – 5,000 | 1,000+ / year | 1 – 500 |
| Typical part | Valve body, manifold, housing | Bushing, adapter, hub | Pin, contact, spool | Impeller, bracket, mould |
Parts outside the turn-mill envelope go to our CNC turning, Swiss machining and CNC milling cells — same plant, same control plan, same engineer on your account.
A print alone gets you a price. These six get you a price, a proposed operation sequence, and the notes that change the number.
The STEP model lets us check reach, tool access and interference before quoting rather than after.
If features are dimensioned from two different references, someone has to choose which relationship to protect. Better that it is you.
One line on the enquiry. It decides whether the part needs a B-axis head, and it moves the price more than anything else on the print.
Even a rough list. It shows what the part costs you today and where the real saving sits.
Four releases of 250 is a different job from one order of 1,000. It changes setup amortisation and what we hold in stock.
FAI format, PPAP level, material certificates, RoHS. Named in the quote so it is not a discussion at first delivery.
You get a DFM response within one business day: the operation sequence we would run, the notes that would make the part cheaper, and questions where the print is ambiguous rather than assumptions built quietly into the price. If a conventional route suits your part better, that is what the reply will say.
CNC turning shapes a rotating part with stationary tools and produces rotational geometry. Mill-turn adds driven tooling, a positionable C-axis spindle, a Y-axis and usually a tilting B-axis milling head, so non-rotational features are machined on the same clamp. The practical difference is setups: a turned part with cross-holes and flats typically needs two or three operations conventionally and one on a turn-mill centre.
±0.005 mm (±0.0002″) on a single controlled feature, ±0.013 mm (±0.0005″) across a production lot at Cpk ≥ 1.33, and 0.010 mm feature-to-feature within one setup. Surface finish is Ra 0.4–1.6 µm as machined and Ra 0.2 µm or better with honing or electropolishing. Which figure applies to your print depends on the datum scheme, material and lot size, and we state it explicitly in the quote.
We hold feature-to-feature position to 0.010 mm within one setup. A conventional four-operation route typically accumulates around ±0.09 mm of positional uncertainty between the first and last feature, using ±0.03 mm per re-fixture as a planning figure. The gain concentrates on concentricity, true position and perpendicularity callouts that span both ends of a part — the relationships a re-clamp cannot preserve and inspection cannot recover.
The term covers a lathe with live tooling and a C-axis, a machine that adds a Y-axis and sub-spindle, and a full multitasking centre with a tilting B-axis milling head. Only the third cuts a compound angle without a fixture. Our Integrex-class centres work at that level, with the B-axis positioned to ±120° and indexed to 0.0001°. If any feature on your drawing sits off the perpendicular, that is the detail worth stating in your enquiry.
Ø150 mm turned diameter, 500 mm overall length, and Ø65 mm bar capacity through the spindle. Larger prismatic components run on our horizontal and 5-axis machining centres, and we will say so at quote rather than stretching the envelope.
No hard minimum. Mill-turn carries meaningful programming and proof-out cost, so on very low quantities we quote the part both ways — turn-mill and conventional route — and show you the difference. On parts with tight cross-face tolerances the single-setup route often wins even at fifty pieces, because the alternative needs a fixture and sometimes a grinding operation.
Stainless steels including 303, 304/304L, 316/316L, 17-4 PH and 440C; aluminium 6061-T6, 6082-T651, 7075-T6 and 2024-T351; brass and copper alloys; carbon and alloy steels including 4140, 4340 and 16MnCr5; titanium Ti-6Al-4V Grade 5 and Grade 23 ELI; superalloys including Inconel 718, Inconel 625, Monel 400 and Hastelloy C276; and engineering plastics including PEEK, PTFE, POM, Nylon 66 and PEI.
Often, yes — send the assembly drawing rather than the individual part drawings so we can see the interfaces. Consolidation works best where a joint exists mainly because no single machine could produce the shape, and where the second piece is smaller than the material being removed anyway. Machining cost rises; part numbers, assembly steps, sealing interfaces and stack-up all fall.
First articles in 6–10 working days from drawing approval, production in 15–20 working days after FAI sign-off. Programming time for compound-angle work is quoted separately and stated up front. Exotic bar and billet stock adds procurement time, and we tell you that at quote rather than at week three.
We sign your NDA — send it with the RFQ and it comes back executed. Drawings stay within the engineering and production team handling your part, are never used in marketing without written permission, and are not shown to other customers. Partner finishing lines receive only the process requirement, not your drawing package.
Upload a 2D print and a STEP file. You get back a price, a lead time, and the operation sequence we would run — plus the specific notes that would make the part cheaper or more manufacturable. Where a conventional route suits your part better, that is what the reply will say.
