When the wall is under one thirteenth of the bore, there is almost no rigidity left to work with. We control clamping force, cutting heat and springback so these parts hold roundness and size after the chuck releases.
Four problems we see on incoming drawings and on parts that failed elsewhere.
A three-jaw chuck loads the wall at three points. The part turns round while clamped and springs back to a triangle once the jaws open. You measure it on the machine, it passes, and it fails at incoming inspection.
Low wall stiffness drops the natural frequency of the part. Above a certain depth of cut the tool starts to rub instead of shear, and the surface turns into a pattern of axial chatter you cannot polish out.
Clamping pressure varies with jaw wear and operator feel. Part 1 measures 0.02 mm out of round, part 20 measures 0.06 mm. The drawing tolerance is 0.01 mm, so the whole run is scrap.
Roughing a 4 mm wall in one pass puts most of the cutting energy into the workpiece. The diameter grows while hot and shrinks back on the bench. Sizing the finish pass on a warm part guarantees a cold part that is undersize.
The method below is what we run on thin walled parts from a single prototype to a 10,000-piece production lot.
A standard self-centering chuck makes point contact at three jaws, so the clamping force concentrates right where the wall is weakest. We move the grip to a thicker shoulder, a boss, or a sacrificial process lug whenever the geometry allows it.
When the design has no stiff feature to grip, we turn a soft bored sleeve or a full-circle pot fixture that spreads the load over 360 degrees of the outside diameter. The part is then clamped lightly, the bore is cut in the same setup, and the final wall is only reached on the last passes. This is the single largest accuracy gain in the whole process.
Roughing removes most of the stock and puts the most heat and stress into the part. We keep it as a separate operation, leave 0.3–0.5 mm on the wall for finishing, and let the part cool to room temperature before the finish pass. On quenched and tempered steel we sometimes run a stress-relief dwell between the two.
Finishing then uses a sharp, positive-rake insert with a small nose radius, a light depth of cut and a higher surface speed. Spring passes at zero depth clean up the residual deflection without loading the wall. Cutting fluid is aimed at the cutting zone, not over the whole part, so thermal growth stays predictable.
Pick the setup from wall ratio, part length and quantity.
| Condition | Setup choice | Why |
|---|---|---|
| Wall ≥ 1/10 of bore | Standard soft jaws | Rigid enough; no fixture cost |
| Wall 1/10 to 1/20 of bore | Bored soft jaws, low pressure | Spreads load, limits ovality |
| Wall < 1/20 of bore | Full-circle sleeve or pot fixture | 360° support stops collapse |
| Length-to-diameter over 3:1 | Tailstock or steady rest | Stops bending and taper |
| Single prototype | One-off sleeve, hand-adjusted | Fast to make, no tooling spend |
| 10,000+ pieces | Dedicated hydraulic fixture | Repeatable pressure every cycle |
Everything a turned part needs, under one roof and one inspection chain.
Live-tool turning and mill-turn work on Ø400 mm rotary capacity, including bores, grooves, threads and arc raceways.
16 mill-turn centers cut cross holes, flats and slots without a second clamping, which matters when the wall is already thin.
16 simultaneous 5-axis centers handle contoured profiles and angled features on turned blanks.
One-off turned prototypes for fit checks before you commit to a production fixture.
Anodizing, plating, black oxide, bead blasting and polishing, all after dimensional inspection.
CMM and roundness checks with reports on request, plus 100% inspection before shipment.
Numbers we work to on thin walled parts.
| Item | Range | Note |
|---|---|---|
| Maximum turned diameter | Ø400 mm | Rotary table capacity |
| Maximum part length | 4,000 mm | Larger travel machines available |
| Wall thickness | 0.5 mm and up | Depends on material and length |
| Diameter tolerance | ±0.005 mm | On stable, supported features |
| Surface finish | Ra 0.2–0.8 μm | Fine turning, supported wall |
| Materials | Aluminium, stainless, steel, copper, titanium | Full list on request |
Six reasons engineers send thin wall work here.
Fifteen years on rotating parts, three wholly-owned plants and 150 technicians.
127 high-precision machines let us match the setup to the part instead of the schedule.
Turning and milling in one clamping keeps thin walls away from a second jaw bite.
Held on diameters, bores and arc features when the setup is right.
Quotation and free DFM analysis within 12 hours of receiving your files.
No MOQ. One prototype or a 10,000-piece run, same process discipline.
Lightweight rotating bodies with arc raceways and strict wall control.
Thin cylindrical sleeves and bushing-type parts in medium to high volume.
Small thin-wall tubes and barrels where roundness drives the assembly fit.
Long, thin-wall rollers that need tailstock support to avoid taper.
It depends on the material, the part length and how much of the wall is unsupported. In aluminium we regularly turn walls around 0.5 mm on short parts. On a 4 mm wall in quenched and tempered steel, the limiting factor is clamping, not the tool.
Send the drawing and we will tell you whether a full-circle fixture is needed or whether bored soft jaws are enough.
Clamping force stores elastic energy in the wall. When the jaws release, that energy comes back and the diameter moves.
The fix is to grip on a thicker section, spread the load over the full circumference, and cut the final wall in the clamped state so the released part is the one you measured.
Usually not. Roughing generates most of the heat, so we separate it and let the part return to room temperature before finishing.
On simple parts with a thick wall we do combine them, because the extra handling is not worth it.
A sharp positive-rake insert with a small nose radius. It lowers radial cutting force, which is what pushes a thin wall away from the tool.
We avoid large nose radii and negative rake on the finishing pass, even though they are more productive on rigid parts.
We measure it in the free state, off the machine, with the part at room temperature. On-machine readings taken while clamped describe the clamped shape, not the delivered part.
For arc raceways and contoured grooves we use a profile check against the drawing radius rather than a point micrometer alone.
±0.005 mm is our standard capability on stable, supported features. On a long unsupported wall the practical limit is looser, and we will say so before quoting.
Where a drawing asks for something the geometry cannot hold, the DFM report flags it within 12 hours.
Yes. Quenched and tempered steels and 17-4PH are common here. Hardness above roughly 42 HRC shortens tool life and raises cutting temperature, so we slow the finishing pass and control cooling more tightly.
Stress relief between roughing and finishing helps on these materials.
Yes. Anodizing, electroless nickel, zinc plating, black oxide, bead blasting and polishing are all available.
Finishing runs after dimensional inspection, so a coating thickness that affects fit is accounted for in the drawing review.
Upload your part file and we will return a quotation with a free DFM analysis within 12 hours. No minimum order quantity, from one prototype to a 10,000-piece run.
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