Contract precision turning · Osaka, Japan
Turned parts in the metals other shops turn away.
For over half a century Nakagawa has machined thin-walled, close-tolerance components from the difficult-to-cut alloys — stainless, titanium and Hastelloy — for sealing, plant and semiconductor applications. Representative case studies, by material.
The problem with hard metals
Corrosion- and heat-resistant alloys earn their keep in service, but they fight the tool. They work-harden under the edge, hold heat at the cut, and spring and distort the moment a wall gets thin. A stable, clean part is a process problem — not a machine you can simply buy.
- Achievable tolerance
- to ±0.005 mm
- Min. wall thickness
- ≈ 0.3–0.5 mm
- Work size
- φ5 mm – φ500 mm+
- Part records
- tens of thousands
- Core strength
- in-house jig / fixture development
- Base
- Joto-ku, Osaka, Japan
Case study · Material 01 / Stainless
Stainless Steel Turning
SUS304 · SUS316 · SUS316L · SUS329J4L (duplex)
Stainless is the workhorse of sealing and plant hardware — and it punishes the tool with work-hardening and trapped heat. On thin-walled gland plates and sleeves, that combination turns into distortion and chatter unless the process is controlled from the first cut.
Austenitic grades such as SUS304 and SUS316 harden rapidly under a rubbing or dwelling edge. Once a hardened skin forms, the next pass sees a tougher material than the drawing assumed — tool wear accelerates, heat builds, and a thin wall begins to move.
Because so much of our work is sealing hardware, the tolerances that matter are flatness, parallelism and concentricity across a large, thin face. A gland plate that measures perfectly at the chuck but relaxes after unclamping is a reject. Our process delivers a part that is stable after it comes off the machine.
- Grades
- SUS304, 316, 316L, 329J4L
- Typical parts
- Gland plates, retainers, sleeves
- Tolerance class
- to ±0.005 mm
- Min. wall thickness
- ≈ 0.3–0.5 mm
- Surface finish
- down to Ra 0.4 µm
- Work size
- φ5 – φ500 mm+
AThe machining challenge
Work-hardening
A dwelling or dull edge glazes the surface. Later passes cut a harder layer, spiking tool wear and cutting force.
Heat concentration
Low thermal conductivity keeps heat at the cut, softening the tool and risking thermal growth.
Thin-wall distortion
Clamping and cutting forces deflect thin sections; the wall springs back out of round once released.
Built-up edge
Gummy chips weld to the insert, degrading finish on visible seal faces.
BOur approach
Constant, positive feed
A steady chip load keeps the tool under the hardened layer instead of skating on top of it.
Sharp, correct geometry
Positive-rake, keen inserts matched to the grade cut cutting force and built-up edge.
Purpose-built workholding
In-house jigs spread clamping load so thin walls are supported, not crushed.
Stress-aware sequencing
Roughing, relief and finishing are ordered so stress releases before the final cut.
CRepresentative parts
// Swap placeholders for product photography before publishing.
DIndustries served
Case study · Material 02 / Titanium
Titanium Turning
Pure Ti Type 2 · TB340 · Ti-6Al-4V
Titanium's strength-to-weight and corrosion resistance make it ideal for chemical, marine and medical parts — and difficult on the lathe. It holds heat at the cutting edge, springs back elastically, and throws fine, reactive chips that demand disciplined handling.
Titanium's thermal conductivity is a fraction of steel's, so heat that would normally leave in the chip stays concentrated at the edge. Run too fast and the tool fails; the answer is measured cutting speed with a genuine, uninterrupted feed and generous coolant.
The metal is also elastic. Under pressure a thin wall deflects then springs back, so a cut that looks correct at the tool reads out-of-round once released. Rigid workholding and light, confident finishing passes bring the part back to print.
- Grades
- Pure Ti Type 2, TB340, Ti-6Al-4V
- Typical parts
- Rings, sleeves, fittings, screws
- Tolerance class
- to ±0.01 mm
- Min. wall thickness
- ≈ 0.5 mm
- Key concern
- heat · spring-back · chips
- Work size
- φ5 – φ500 mm+
AThe machining challenge
Heat at the edge
Low conductivity concentrates heat in the cutting zone, shortening tool life and risking dimensional change.
Elastic spring-back
Titanium deflects under load and recovers after, so thin walls finish out-of-round unless pressure is controlled.
Chemical reactivity
At temperature titanium reacts with many tool materials, causing galling and rapid edge breakdown.
Reactive fine chips
Fine chips are combustible; safe evacuation and coolant flooding are essential.
BOur approach
Controlled speed, real feed
Moderate surface speed with steady feed keeps the edge below its critical temperature while still cutting cleanly.
Flood coolant
High-volume coolant pulls heat from the cut, protects the edge and flushes fine chips clear.
Rigid, distributed clamping
Fixtures that grip firmly without crushing counter spring-back on thin rings and sleeves.
Light finishing strategy
Final passes take out the elastic deflection so the released part sits on size and round.
CRepresentative parts
// Swap placeholders for product photography before publishing.
DIndustries served
Case study · Material 03 / Hastelloy & Alloy
Hastelloy & Alloy 20 Turning
Hastelloy C276 · Alloy 20 (Carpenter 20Cb3)
Hastelloy C276 and Alloy 20 resist the harshest corrosive and high-temperature service — which is exactly why they resist the tool. They work-harden aggressively, hold their hardness hot, and cost enough that every part has to come out right the first time.
These nickel alloys are prized for corrosion and heat resistance, so they appear in plant and energy equipment that must survive environments ordinary stainless cannot. The same toughness makes them punishing to cut: they work-harden fast, retain hardness hot, and wear tools quickly.
Because a Hastelloy blank is a serious material cost, there is little tolerance for a scrapped part. Nakagawa's extensive record on these alloys — knowing the parameters that keep the edge under the hardened layer — is what keeps the reject rate down.
- Grades
- Hastelloy C276, Alloy 20
- Typical parts
- Gland plates, sleeves, flanges, discs
- Tolerance class
- to ±0.01 mm
- Material trait
- high hardness · work-hardening
- Service
- corrosion & heat resistant
- Work size
- φ5 – φ500 mm+
AThe machining challenge
Severe work-hardening
The alloy hardens instantly under a hesitating edge; the next pass meets a far tougher skin.
Hot hardness
It keeps its strength at cutting temperature, so heat does not soften the job — it just wears the tool.
Rapid tool wear
Abrasive, tough chips break down inserts quickly, demanding the right grade and disciplined change-out.
Cost of failure
Expensive stock means a single mistake is costly — the process must be right before the first cut.
BOur approach
Rigid setup, no chatter
Maximum rigidity in tool and workholding stops the vibration that triggers work-hardening and defects.
Purposeful, unbroken feed
A committed feed keeps the edge cutting fresh material beneath the hardened skin rather than glazing over.
Correct insert grade
Tool grade and geometry are chosen for the alloy so wear is predictable and edges change before they fail.
Experience-led parameters
Parameters from an extensive Hastelloy / Alloy 20 record keep the reject rate and material waste down.
CRepresentative parts
// Swap placeholders for product photography before publishing.
DIndustries served
Have a difficult turned part on your desk?
Send a drawing (2D/3D) and we will assess machinability, tolerances and lead time — including VA/VE proposals to reduce cost without compromising function.
Company
Nakagawa Precision Machinery Works Co., Ltd.
Address
2-5-17 Sekime, Joto-ku, Osaka, Japan
Hours
9:00–17:00 JST (excl. weekends & holidays)
