Swiss Machined Fasteners & Threaded Components
We produce precision fasteners — screws, bolts, standoffs, inserts, custom threaded parts — on Swiss-type sliding headstock machines. From Ø0.5 mm micro fasteners to Ø32 mm structural hardware, with thread tolerances held to 4h/4g and dimensions verified on Mitutoyo CMM.
Why Swiss Machining Produces Better Fasteners
A Swiss-type (sliding headstock) lathe differs from a conventional CNC lathe in one critical way: the bar stock moves axially through a fixed guide bushing while the cutting tools remain stationary. The workpiece is always supported within 1–2 mm of the cut. For small-diameter threaded components — where deflection during threading is the primary source of pitch diameter error — this rigid support is the mechanical reason Swiss machining consistently outperforms standard CNC turning on fastener quality.
If you are evaluating Swiss machining for other small-diameter or high-precision turned parts, you can also explore our Swiss CNC machining services to learn more about our machine capacity, tolerances, materials, and part families.
No deflection during threading
The guide bushing constrains bar runout to <0.01 mm. Thread pitch diameter scatter is predictable and repeatable lot to lot.
Complete in one setup
OD turning, threading, cross-drilling, slotting, and part-off happen in a single cycle. No re-chucking — no re-chucking error.
Slender parts without distortion
L/D ratios up to 12:1 machined without chatter or deflection — practical for shoulder bolts, long standoffs, and guide pins.
High volume, consistent quality
Bar-fed automation runs lights-out with SPC-controlled process. CPK >1.33 achievable on thread classes 4h/4g and tighter.
Swiss vs. Conventional CNC Turning
Both processes produce turned fasteners. The difference shows up at tighter tolerances, smaller diameters, and higher volumes.
| Attribute | Swiss-Type | Conv. CNC |
|---|---|---|
| Min. bar diameter | Ø0.5 mm | ~Ø6 mm |
| Support near cut | Guide bushing — always | Chuck only — far from cut |
| Thread pitch dia. scatter | <0.005 mm | 0.01–0.02 mm typical |
| L/D capability | Up to 12:1 | 3:1 practical limit |
| Slotting / cross-drilling | Live tooling in-cycle | Separate op required |
| Best for | M1–M20, small precision parts | M20+ larger hardware |
| High-volume economics | Bar-fed, near-continuous | Requires frequent loading |
Fasteners & Threaded Components We Produce
We machine fasteners and threaded components to customer drawings — not catalog standards. If your application needs a non-standard thread form, special head geometry, cross-hole, or proprietary drive feature, send us the drawing. We treat every fastener as a precision part, not a commodity.
Socket Head Cap Screws
Swiss-turned socket head cap screws with tight-tolerance shank diameters and fully formed metric or inch threads. We produce hex, Torx, and proprietary socket profiles, including security variants with tamper-resistant features machined in-cycle.
Hex Head Bolts & Machine Screws
Full-form machined hex head bolts with wrench-flat tolerances maintained to DIN 933 / ISO 4014 or customer-specified head dimensions. Shank undercut, grip length, and transition radius machined to drawing in one setup.
Precision Standoffs & Spacers
Hex, round, and square standoffs with controlled OAL tolerance (±0.05 mm standard, ±0.01 mm on request) and fully tapped through-holes in metric or unified thread. Internal thread class 4H/5H held throughout production via in-process gauging with no-go plug checks.
Threaded Inserts & Nut Bodies
Externally threaded inserts for plastics and soft materials, internally threaded nut bodies, and keensert-style locking inserts. OD thread class 3A/6g for press or adhesive fit; ID thread class 4H with full form verification on optical projector.
Shoulder Bolts & Precision Pins
Shoulder diameter held to h6 tolerance (±0.004 mm on Ø6 mm) for bearing/bore fits. Shoulder length, thread runout, and head perpendicularity to shoulder all measured on CMM before release. Common applications include pivot pins, guide bolts, and dowel-locating fasteners.
Specialty & Non-Standard Fasteners
When catalog items don't fit your assembly — custom thread pitch, proprietary head form, integrated features (cross-hole, groove, flat, knurl), or unusual material requirements — we machine to your drawing. We've produced drive pins for POGO PIN connectors, fasteners for ultra-high-pressure valve bodies, and titanium hardware for aerospace assemblies.
The Swiss Machines Producing Your Parts
We run dedicated Swiss-type and CNC lathe platforms — all imported from Japan — with bar feed automation. The machines below are what’s physically on our floor, not marketing inventory.
CITIZEN A20 — Swiss Sliding Headstock
The core machine for precision small-diameter fasteners. Sliding headstock with guide bushing supports the bar through Ø25 mm. Live tooling stations machine cross-holes, flats, and secondary features in the same cycle as threading.
- Bar capacityØ0.5 – 25 mm
- Dim. tolerance±0.005 mm
- Thread tolerance4h / 4g achievable
- Live toolingMilling, drilling, tapping
CITIZEN A16 — Micro Swiss Lathe
Dedicated to the micro end of our range — Ø0.5 to Ø15 mm. Thread pitch diameter scatter consistently below 0.003 mm on M2 and smaller. Used for miniature instrument screws, connector hardware, and micro standoffs.
- Bar capacityØ0.5 – 15 mm
- Dim. tolerance±0.005 mm
- Ideal thread rangeM1 – M10
- Surface finishRa ≤ 0.8 μm
TSUGAMI B206 — CNC Swiss Lathe
High-rigidity Swiss lathe with bar feed automation. B206 is our go-to for high-volume medical and semiconductor fasteners where surface finish and repeatability over long runs are critical. Excellent for stainless and titanium threading.
- Bar capacityØ1 – 20 mm
- Dim. tolerance±0.005 mm
- Material strengthStainless, titanium, brass
- Volume capabilityHigh — bar feed auto
NOMURA 1085 — Automatic Swiss Lathe
Cam-driven automatic lathe for extreme-volume runs of simple fastener profiles. Cycle time per part in the sub-second range on straightforward geometries. Used when millions of small fasteners with consistent thread form are required at lowest unit cost.
- Bar capacityØ1 – 6 mm
- Dim. tolerance±0.005 mm
- Best forHigh-vol simple geometry
- OriginJapan
MAZAK CNC Lathes — Multiple Models
Larger-diameter fasteners from Ø20–150 mm, including hex bolts, large standoffs, and structural threaded components, are produced on MAZAK turning centers with live tooling. Full 36-unit fleet with consistent tooling standards.
- Bar / chuck capacityØ20 – 150 mm
- Live toolingYes — milling, drilling
- Thread sizeM16 – M48 and custom
TSUGAMI B-series — High-Volume Swiss
Dedicated to rapid bar-feed production of mid-range fasteners. B-series machines run 24/7 on long-run programs. With 28 units, this is where we absorb volume spikes on fastener programs without impacting lead times on other customers.
- Bar capacityØ1 – 32 mm
- Dim. tolerance±0.005 mm
- Operation modeBar feed, lights-out capable
Thread Classes, Tolerances & Standards We Work To
Metric Thread Standards (ISO 965)
| Thread Class | Application | Pitch Dia. Tol. (M6) |
|---|---|---|
| 4g / 4h | Precision fit, minimum clearance | ±0.030 mm |
| 6g / 6H | Standard commercial fit | ±0.060 mm |
| 3A / 3B | Close fit (unified inch) | ISO 1 equiv. |
| Custom | Proprietary thread form | To drawing |
Unified Inch Thread (ASME B1.1)
| Thread Range | Series | Class |
|---|---|---|
| #0–80 – #10–32 | UNF | 2A / 3A ext. |
| 1/4–28 – 1/2–28 | UNF | 2A / 3A ext. |
| 1/4–20 – 3/4–10 | UNC | 2A / 2B |
| Special pitch | UNEF / custom | To spec. |
Thread gauging on every lot: We use calibrated ring gauges (GO/NOGO) and plug gauges on all threaded fasteners. CMM thread measurement available for pitch diameter, lead, and flank angle verification on first articles and qualification runs. All gauges maintained under ISO 10012-certified calibration.
Dimensional Tolerances — Fastener Features
| Feature | Standard | Achievable |
|---|---|---|
| OD / major diameter | ±0.010 mm | ±0.005 mm |
| Thread pitch diameter | Class 6g | Class 4g |
| Shoulder diameter | h7 | h6 / g6 |
| OAL (overall length) | ±0.10 mm | ±0.02 mm |
| Head height | ±0.05 mm | ±0.02 mm |
| Socket depth | ±0.10 mm | ±0.05 mm |
| Cross-hole position | ±0.05 mm | ±0.02 mm |
| Runout to shank | 0.02 mm TIR | 0.01 mm TIR |
| Surface finish (shank) | Ra 1.6 μm | Ra 0.8 μm |
Head Drive Standards We Machine
| Drive Type | Standard | Min. Size |
|---|---|---|
| Hex socket (Allen) | ISO 4762 / DIN 912 | M1.6 |
| Torx / Torx Plus | ISO 10664 | M2 |
| Phillips / Pozidrive | ISO 8764 | M1.6 |
| Slotted | ISO 1207 | M1 |
| Security (tamper-resist) | To drawing | M2 |
| External hex / hex flange | DIN 933 / 6921 | M3 |
Fastener Materials We Machine
Fastener material selection directly affects corrosion resistance, thread galling risk, fatigue life, and coefficient of friction — all of which matter in industrial, aerospace, and medical applications. We machine all of the following, and can advise on material selection during DFM review.
Stainless Steel
303 (free-cutting), 304, 316L (low carbon, weld-safe), 316F (improved machinability), 17-4 PH (precipitation hardening), 440C (high hardness)
Medical implant tools · UHP semiconductor fittings · Marine hardware · Chemical process fasteners
Titanium
Grade 2 (commercially pure, corrosion-resistant), Grade 5 / Ti-6Al-4V (high strength, aerospace standard)
Aerospace structural fasteners · Medical device hardware · High-performance motorsport bolts
Brass & Copper
C360 (free-machining brass — fastest cycle), C260 (cartridge brass), C932 bearing bronze, ETP copper
Electrical connectors · Standoffs in PCB assemblies · Flare fittings · RF/EMI shielding hardware
Alloy & Carbon Steel
1018, 1045, 4140 (Cr-Mo), 4340 (high strength), 12L14 (free-cutting), SUM22L
Industrial machinery bolts · Automotive powertrain hardware · High-tensile structural fasteners
Aluminum
6061-T6, 7075-T6, 2024-T4, 5052 (marine grade)
Lightweight aerospace standoffs · Electronics chassis hardware · Weight-critical assemblies
Inconel & Superalloys
Inconel 625, Inconel 718 (on request), Monel 400
High-temperature applications · Jet engine hardware · Corrosive environment fasteners
Surface Finishing for Fasteners
Passivation (ASTM A967)
Standard for stainless fasteners — removes free iron, restores native Cr₂O₃ passive layer. Does not change dimensions.
Electroless Nickel (EN)
Uniform 0.0002–0.0005″ deposit — predictable build-up allows pre-plate allowance on threaded parts. Hardness 48–52 HRC after bake.
Zinc Phosphate + Oil
For steel fasteners — base coat for paint adhesion or stand-alone corrosion inhibition. Adds minimal dimensional change.
Anodizing — Type II / III
Type II (cosmetic + light corrosion protection) or Type III hard anodize (0.0005–0.001″ build) for aluminum fasteners. Pre-plate threading recommended.
Black Oxide
Minimal dimension change (<0.00015″), mild corrosion resistance, non-reflective finish. Common on steel socket head fasteners.
Electropolish (EP)
Removes surface layer to Ra ≤ 0.2 μm — standard for semiconductor and bio-pharma fasteners where particle generation is a concern.
PTFE / Dry Film Lubrication
Reduces galling risk on stainless and titanium threads — critical for fasteners assembled and disassembled repeatedly in the field.
As-Machined
Ra ≤ 0.8 μm standard from the Swiss machines. Burr-free guaranteed through process controls, not secondary deburring stations.
Numbers That Appear on Our CMM Reports
The tolerances below are not theoretical — they're drawn from our ongoing production data on Swiss-turned fasteners. Every first article includes a full CMM report. Production lots are monitored with SPC where customer programs require it.
Thread Inspection Reference
| Feature | Method | Accuracy |
|---|---|---|
| Thread pitch diameter | Ring gauge GO/NOGO | Per tolerance class |
| Major diameter | Mitutoyo CMM | ±0.001 mm |
| Thread lead / pitch | Optical projector | ±0.001 mm |
| Flank angle | Contour profiler | ±0.5° |
| OAL / grip length | CMM / height gauge | ±0.001 mm |
| Runout (TIR) | CMM rotary scan | 0.001 mm resolution |
| Head socket depth | 2.5D optical | ±0.001 mm |
Standard dimensional tolerance
Held across all CITIZEN and TSUGAMI platforms on OD, shoulder, and head features. Tighter on request — ±0.002 mm on specific features during DFM review.
Tight thread tolerance class
Precision class for minimum-clearance thread fits. Standard production on CITIZEN machines running M2–M16. Verified with calibrated ring gauges, every lot.
Shoulder bolt tolerance
IT grade 6 on shoulder diameters up to Ø25 mm. Enables direct bearing, bushing, or bore fits without secondary grinding operations.
As-machined surface finish
Achieved from the machine — no secondary polishing. Shank and bearing surfaces consistently below Ra 0.8 μm. EP finishing brings this to Ra ≤ 0.2 μm.
CMM measurement accuracy
Mitutoyo CMM on site — first articles fully measured. All inspection equipment under ISO 10012-certified calibration.
Who Buys Swiss-Machined Fasteners from Us
We do not produce fasteners for consumer products. Our customers are OEMs and contract manufacturers in industries where fastener failure has real consequences.
Semiconductor Equipment
Ultra-clean fasteners for process chamber assemblies, valve bodies, and gas handling systems. Electropolished 316L, no burrs, particle-free packaging. Experience with SEMI F20 cleanliness requirements.
Aerospace & Defense
AS9100D certified. Titanium Grade 5 and 17-4 PH structural fasteners, shoulder bolts for actuation systems, and specialty hardware with full material traceability and first article inspection reports per AS9102.
Medical Devices
Surgical instrument screws, implant tool fasteners, and diagnostic equipment hardware. Biocompatible material selection (316L, Ti-6Al-4V), surface finish documentation, and lot traceability to individual bar stock heat.
Automotive
IATF 16949 certified. Sensor housing fasteners, powertrain hardware, ADAS bracket bolts, and EV charging connector standoffs. PPAP Level 1–3 available. Harman, Bose, and JBL production experience.
Electronics & PCB Assembly
Brass and stainless standoffs, through-hole spacers, and PCB mounting hardware. Thread class 4H tapped holes, controlled OAL for stack height management, and RoHS-compliant plating with XRF verification.
Industrial & Robotics
Shoulder bolts for robot pivot joints, custom thread-form fasteners for linear guides, and high-strength 4340 hardware for heavy industrial machinery. We've produced components for Hyundai Robotics assemblies.
How We Verify Every Threaded Component
For fasteners, quality control focuses on three families of checks: thread form, dimensional accuracy, and surface integrity. Our QC team uses a combination of CMM measurement, optical projection, ring/plug gauging, and vision-based automatic sorting — not just go/no-go gauging alone.
IATF 16949:2016
Automotive quality management system. Covers APQP, PPAP, FMEA, MSA, and control plan requirements for all automotive fastener programs.
AS9100D
Aerospace quality management. First article inspection per AS9102, nonconformance management, configuration control, and lot traceability.
ISO 10012:2003 — Measurement Management
Every ring gauge, plug gauge, CMM probe, and optical system is under a documented calibration cycle with traceable standards. Calibration records available on request.
RoHS / Substance Testing
Seiko SII SEA1000A X-ray fluorescence on site. Plating and coating substance verification on production lots — report available with every shipment.
Thread & Dimensional Inspection Equipment
Why Engineers Specify Richconn for Swiss Fasteners
We've heard the same reasons from procurement engineers, quality managers, and design leads at our customers. These are the real differentiators.
Micro to Standard Range in One Supplier
M1 micro screws and M20 structural bolts, from the same QMS. You don't need a different vendor for your smallest fastener.
To-Drawing, Not To-Catalog
We don't adapt catalog fasteners. Every part is machined to your drawing — thread class, head form, material, and finish as specified, not approximated.
Thread Class Held With Gauging, Not Assumed
Every lot is gauged with calibrated ring and plug gauges. You receive the gauge records, not just a CoC signature. ISO 10012 calibration applies to every gauge on the floor.
Three Certifications, One Facility
IATF 16949 + AS9100D + ISO 10012. If your program crosses automotive and aerospace on the same BOM, we satisfy both simultaneously.
Complete From Bar to Finish
CNC machining, threading, passivation, plating, EP, anodizing — all coordinated by us. One PO, one set of documents, one source of accountability.
Volume Without Delivery Drift
80+ CNC and Swiss lathes running concurrently. A large production run for one customer doesn't compress our capacity for another. We hold schedules.
Questions We Get from Engineers & Procurement
In ISO 965 metric threading, the number refers to tolerance grade and the letter to fundamental deviation. A lower number = tighter tolerance. 4g (external) / 4H (internal) is the precision class — less clearance, better fit repeatability, more demanding to produce. 6g / 6H is the standard commercial class with wider tolerance bands and easier assembly.
For most industrial applications, 6g is correct. Specify 4g when: you need minimum thread clearance in a precision fit, the fastener will be used as a guide element, or your mating part is also 4H and designed for a snug fit. If uncertain, share your assembly drawing and we'll advise during DFM review at no charge.
Thread galling on stainless (and especially titanium) is a real concern — the native oxide layer breaks down under the friction and pressure of assembly. We address it through: (1) tight surface finish on thread flanks (Ra ≤ 0.8 μm from the machine reduces the contact area roughness that initiates galling), (2) PTFE dry film or molybdenum disulfide coating on the thread, and (3) careful control of thread tolerance class so there's appropriate clearance without slop. For titanium fasteners in repetitive assembly applications, we strongly recommend specifying a dry film lubricant in your drawing. We can advise on coating compatibility with your application.
We don't publish a fixed MOQ. Practically, for Swiss-machined fasteners, tooling setup and first article inspection add a fixed cost that makes very small quantities (under 50–100 pieces) expensive per-unit. We're most competitive at quantities from 500 pieces upward, and very competitive at 10,000+. For prototyping and qualification, smaller quantities are accommodated — we'll be transparent about setup cost in the quote so you can make a fully informed decision.
This is a critical detail that catches many customers off guard. Electroless nickel (the most common plating we apply) deposits approximately 0.0002–0.0005" (5–13 μm) uniformly, including inside thread roots. If you specify a finished thread class of 4g and then plate, the plating will shift the effective thread outside the tolerance band. We work with you to calculate pre-plate thread dimensions: we machine the thread undersized by the plating allowance so the post-plate thread lands in the correct tolerance class. Always specify your dimensional requirements as post-plate — we handle the pre-plate compensation.
Yes, we machine to customer drawings referencing NASM, AN, MS, and custom aerospace standards. We do not self-certify to MIL-spec as a distributor — we manufacture to your drawing which references those standards, and our documentation reflects compliance to the dimensions and materials called out on that drawing. Our AS9100D certification covers the manufacturing quality system. You provide the drawing; we build and certify to it.
Standard: Certificate of Conformance, material mill cert (traceable to heat/lot), dimensional inspection report (sampling or CMM), and gauge calibration record. For automotive: PPAP documentation up to Level 3 including control plan, FMEA, and MSA results. For aerospace: first article inspection report per AS9102, and process flow document. RoHS XRF test reports available on request. All documents are lot-traceable to the specific shipment.
Yes. We perform reverse engineering from physical samples — we measure the sample on CMM, profile the thread on our contour projector, identify the drive feature geometry, and produce a dimensioned drawing for your review before machining. Material identification is performed via XRF analysis and, if necessary, third-party spectrographic testing. This is a common request for fasteners used in legacy equipment where original drawings no longer exist.
For standard materials (303 SS, C360 brass, 6061 aluminum): quote within 48 hours, first article parts in 10–15 working days, production 20–35 working days after first article approval. For special materials (Ti-6Al-4V, Inconel, 17-4 PH): add 5–10 working days for material procurement. For programs requiring PPAP: add time for the submission and customer approval cycle. We recommend starting any new fastener qualification 8–12 weeks before your production need date — this absorbs any first article revision cycles without compressing your schedule.
Send Us Your Fastener Drawing
Share your drawing, sample, or specification. We’ll review the thread class, material, finish, and quantity — and have a quote back to you within 24–48 hours. DFM feedback is included at no charge.
- Quote within 24–48 hours
- To-drawing production — no catalog substitutions
- IATF 16949 + AS9100D + ISO 10012 certified
- Thread class gauged and documented, every lot
- Ø0.5 – Ø32 mm on Swiss machines; up to Ø150 mm on turning centers
- Reverse engineering from physical samples accepted
