What Is Swiss CNC Machining?
Swiss CNC machining (also known as Swiss screw machining or sliding headstock turning) feeds bar stock through a stationary guide bushing directly adjacent to the cutting tool. Because the material is supported right where the cut happens, deflection and vibration are eliminated — allowing ultra-tight tolerances, micro features, and length-to-diameter aspect ratios over 20:1 that conventional CNC lathes cannot achieve.
Bar Stock Feeds Through Guide Bushing
The raw bar feeds through a carbide-lined guide bushing, providing zero-clearance support right next to the cutting insert.
Sliding Headstock Moves Along Z-Axis
Instead of moving the cutting tool along the part, the headstock advances the bar past fixed gang tooling, maintaining maximum rigidity.
Live Tooling & Sub-Spindle Dual Machining
Cross-milling, axial drilling, threads, and back-side features are completed in a single setup before parting off the finished part.
The City That Builds the 737 Runs on Small Turned Parts
Renton's manufacturing identity was set in the 1940s, when the Boeing plant on the south shore of Lake Washington built B-29 Superfortresses, and it never let go. The same site produced the 707, the 727 and the 757 before settling into its modern role as the highest-rate commercial aircraft factory on earth, assembling every 737 MAX variant plus the airframes that become P-8 Poseidon patrol aircraft. A single 737 contains roughly 400,000 parts, and a meaningful share of them are exactly what a Swiss lathe exists to make: pins under a quarter inch in diameter, threaded standoffs, hydraulic fittings and contact pins with length to diameter ratios a conventional lathe cannot hold straight.
The supplier ring around the factory reflects that. Exotic Metals Forming works titanium and nickel superalloys less than a mile from the factory gate, GKN Aerospace feeds fuselage stringers up from Auburn and Safran Landing Systems supplies titanium gear components. Renton is not only aircraft, either. Kenworth has assembled Class 8 trucks in the city for decades, which keeps a steady population of fitters, hydraulic techs and purchasing teams who buy turned spools, ferrules and sensor housings on repeat schedules.
RivCut serves this ecosystem from Union City, CA with sliding headstock Swiss lathes. The guide bushing supports bar stock right at the tool, so a 3 inch long pin at 0.125 inch diameter comes off round and concentric to 0.0002 inches TIR, finished near Ra 16 microinches as machined, with live tooling and sub-spindle work completing cross-holes, flats and back-side features in one setup. Ground transit to Renton runs 1 to 2 business days.
Engineered for Micro-Precision & High Volume
From single medical prototypes to automated 100,000+ piece production runs — built for zero defect manufacturing.
±0.0001" Micro Tolerance
Holding ultra-precise concentricity, diameter, and thread pitch tolerances on slender pins, shafts, and medical implants where standard lathes fail.
Single-Setup Completion
Multi-axis live tooling and sub-spindles handle turning, off-center milling, cross-drilling, hex broaching, and thread whirling with zero secondary setups.
Superior Ra 16 Surface Finish
Rigid guide bushing support eliminates chatter and micro-vibration, consistently producing mirror-smooth Ra 16 µin (0.4 µm) turned surfaces as-machined.
Lights-Out Production Savings
Automatic bar feeders and continuous chip management allow 24/7 un-attended operation, dramatically lowering unit costs for mid-to-high volume orders.
Swiss Machining Services Suite
Sliding headstock capabilities engineered for challenging small-diameter components.
Micro-Miniature Turning
Machining small-diameter components down to 0.020" (0.5 mm) with tight features, internal bores, and miniature threads for medical instruments and micro-valves.
Down to 0.5 mm barHigh L/D Ratio Slender Shafts
Turning long, slender shafts and pins with length-to-diameter ratios up to 20:1 without chatter, taper, or deflection.
L/D up to 20:1Multi-Axis Live Tooling
Up to 12 axes with motorized driven tools for off-center milling, keyways, cross-drilled passages, hex flats, and helical thread whirling.
Up to 12-axis liveDual-Spindle Sub-Machining
Synchronized pick-off sub-spindle finishes the back end of the part—chamfering, counterboring, and tapping—delivering 100% complete parts off the line.
100% finished partsMedical & Implant Machining
Precision turning of Titanium Ti-6Al-4V ELI bone screws, dental implant posts, orthopedic pins, and endoscope tips with ISO 13485 quality control.
Titanium & 316L medicalHigh-Volume Bar Fed Runs
Automated 12ft bar loaders, high-pressure coolant (2,000 PSI), and automated part catchers support fast production runs from 500 to 100,000+ pieces.
500 to 100,000+ pcs
Titanium Grade 5 Dental Implant Post & Bone Screw
Swiss turned for a medical device manufacturer requiring intricate thread geometry, micro-cannulation through-holes, and tight hex drive features. Machined in a single operation with zero hand deburring required.
tolerance held
surface finish
turnaround
2,500-piece run
- Optical comparator & CMM dimensional inspection report
- Mill test certs (EN 10204 3.1) with heat lot traceability
- Passivation certs per ASTM A967 / ASTM F86
- Certificate of Conformance per medical purchase order
Swiss Turning vs. Standard Lathe vs. CNC Milling
Choose the right manufacturing method based on geometry, tolerances, and batch size.
Stocked Materials for Swiss Turning
Precision ground round bar stock in metals, medical alloys, and engineering plastics.
Titanium Alloys
Ti-6Al-4V (Grade 5), Ti-6Al-4V ELI (Grade 23), Commercially Pure Titanium (Grade 2). Ideal for biocompatible implants, dental screws, and aerospace pins.
Stainless Steels
303, 304/304L, 316/316L, 17-4 PH, 440C, Custom 455. Excellent corrosion resistance, high tensile strength, and medical compliance.
Copper & Brass Alloys
C36000 Free-Cutting Brass, C17200 Beryllium Copper, Tellurium Copper C14500. Perfect for gold-plated electrical contacts and probe tips.
Specialty & Superalloys
Inconel 718, Kovar, Nitronic 60, Hastelloy C-276, Nitinol. High-temperature and controlled-expansion applications for aerospace and energy.
Medical Plastics
PEEK (Unfilled & 30% Glass Filled), Delrin (POM-H), PTFE (Teflon), Ultem 1000, Torlon 4203. Biocompatible, autoclavable, and dimensionally stable.
Alloy & Tool Steels
4140, 4340, A2, D2, M2 tool steel. High wear resistance and toughness after vacuum heat treating for mechanical shafts and dowels.
DFM Tips for Swiss Turned Parts
Optimize your 3D CAD models and drawings for maximum Swiss machining efficiency.
1. Precision Ground Bar Stock
Because the bar slides through a guide bushing, use h8 diameter tolerance precision ground bar stock to prevent binding or loose play.
2. Thread Relief Grooves
Provide a thread relief necking groove at thread shoulders (minimum 1.5x thread pitch) to allow clean single-point thread tool retraction.
3. Corner Radii & Chamfers
Specify internal corner radii of at least R 0.010" (0.25 mm) and external 45° lead-in chamfers to ease automated tool engagement and deburring.
What Renton Teams Send to Our Swiss Lathes
What Renton buyers actually order, sector by sector.
Commercial Aerospace
Tier 2 and Tier 3 shops feeding the 737 MAX line buy turned hardware in bar-fed volumes: clevis pins, shear pins, threaded standoffs, bulkhead fittings and wire-harness contact pins. Rate increases at the Boeing Renton Factory ripple straight into those purchase orders. RivCut turns them from 2024 and 7075 aluminum, 303 and 15-5 PH stainless and Ti-6Al-4V with mill certs, AS9102-style first article reports and lot traceability on every shipment, from 500 pieces to 100,000 plus.
Defense & Maritime Patrol
Every P-8 Poseidon starts as a Renton-built structure, and the program's ITAR footprint extends to the smallest turned component on the aircraft. Sensor housings, valve spools, connector pins and antenna mount hardware for defense work need US-person handling and a documented chain of custody as much as they need tight tolerances. RivCut is ITAR-registered and machines these parts domestically with concentricity to 0.0002 inches TIR, which matters when a spool has to seal in an actuator body at altitude.
Heavy Truck & Industrial Equipment
Kenworth's Renton assembly plant and the maintenance economy around it consume a different diet of turned parts: hydraulic ferrules, grease fittings, gauge pins, wear bushings and slender sensor shafts for chassis and powertrain instrumentation. These are 4140, 12L14 and 17-4 PH jobs where price per piece decides the vendor. Bar-fed Swiss turning with lights-out running gets unit costs down at 1,000 to 50,000 piece quantities while still holding diameters most screw machine shops quote as grinding operations.
Common Questions from Renton Teams
How Swiss turning, quoting and shipping work for Renton teams.
Swiss Machining in the Renton Region
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