Precision Bar Stock Engineered for Swiss-Type CNC Lathes & Bar Feeders
Running high-volume turned titanium components on Swiss-type sliding-headstock CNC lathes (such as Star, Citizen Cincom, Tsugami, or Tornos) and multi-spindle automatic bar machines places strict demands on raw bar stock geometry. Standard hot-rolled or rough-peeled Titanium Rods exhibit diameter drift, out-of-roundness lobing, and bow that cause violent bar whip inside high-RPM feed tubes and catastrophic galling inside carbide guide bushings.
Through our certified partner facilities, we supply bar-feeder ready centerless-ground titanium round bar tailored for CNC Machine Shops, custom EDC hardware turners, motorsport fastener manufacturers, and subsea instrumentation producers. Every shipment is accompanied by a Material Test Certificate (MTC) with heat-lot traceability and Certificate of Conformance (CofC).
Diameter, Length & Grade Specifications
Our partner network processes both metric and Imperial fractional centerless-ground bars to match your exact collet and guide-bushing bore sizes:
| Parameter | Specification Range |
|---|---|
| Ground Diameter Range | Ø 3.0–50.8 mm (0.118"–2.000") |
| Popular Imperial Fractional Sizes | 3.18 mm (1/8"), 4.76 mm (3/16"), 6.35 mm (1/4"), 7.94 mm (5/16"), 9.53 mm (3/8"), 12.70 mm (1/2"), 15.88 mm (5/8"), 19.05 mm (3/4"), 25.40 mm (1.000") |
| Cut Length Range | 1,000–3,000 mm (39.4"–118.1") — custom cut lengths evaluated per bar-feeder magazine specification |
| ISO 286-2 Tolerance Classes | Unilateral negative h6, h7, h8, h9 (specific tolerance band evaluated per nominal diameter and locked in order confirmation) |
| End Preparation | Chamfered and deburred ends for smooth automatic collet and guide-bushing entry |
| Straightness & Roundness | Precision rotary-straightened prior to multi-pass centerless grinding; evaluated per drawing and batch quantity |
Grades Supplied with Multi-Standard Cross-Reference
- Grade 5 (
Ti-6Al-4V|UNS R56400|Werkstoff 3.7165|ВТ6): The primary alloy for CNC-turned pivot barrels, custom thumb studs, motorsport studs, and high-strength mechanical shafts. - Grade 23 (
Ti-6Al-4V ELI|UNS R56407|Werkstoff 3.7165-ELI|ВТ6С): Extra-Low Interstitial grade with tightly controlled oxygen content for precision surgical/instrument components and subsea sensor stems. - Grade 2 (
Commercially Pure Titanium|UNS R50400|Werkstoff 3.7035|ВТ1-0): Selected for seawater valve stems, chemical dosing pins, and corrosion-critical fluid fittings.
Why ISO 286-2 Unilateral Negative Tolerances (h6 / h7 / h8 / h9) Matter
In a Swiss-type CNC lathe, the workpiece is supported by a stationary or synchronous rotating guide bushing just millimeters behind the turning insert. Unlike a conventional 3-jaw chuck lathe that clamps short blanks, a Swiss guide bushing requires the entire 1,000–3,000 mm (39.4"–118.1") length of the bar to pass through a pre-adjusted bushing bore:
- Zero Positive Deviation (
+0Upper Limit): Under the ISO 286-2hshaft system (h6,h7,h8,h9), the upper deviation is strictly zero, and all permissible diameter variation sits on the negative side. Because titanium has a strong tendency to gall against carbide and steel, any oversize spot (+deviation) on a bar will immediately jam and cold-weld inside the guide bushing. - Preventing Overhang Deflection & Chatter: Conversely, if the bar diameter drops too far below nominal, excessive radial clearance inside the guide bushing allows the titanium bar to deflect away from the cutting tool ( accentuated by titanium’s low elastic modulus), causing dimensional taper, poor surface roughness, and insert chipping.
- Selecting Your Tolerance Class:
h6/h7: Recommended for tight-clearance Swiss guide bushings, thin-wall turned sleeves, and micro-threads where radial runout must be minimized.h8/h9: Ideal for collet-fed CNC turning centers, multi-spindle bar automatics, and parts where the entire outer diameter is turned down during the cycle.
You can look up the exact ISO 286-2 tolerance band for your target metric or Imperial diameter in real time using our interactive Tolerance Calculator, and lock the required class directly into your quotation and order confirmation. For a broader comparison of black-skin/peeled bar versus ground stock, read our engineering guide on Titanium Round Bar vs Ground Bar.
Bar-Feeder Ready Workshop Controls
To ensure uninterrupted “lights-out” bar feeding, our certified partner facilities apply three dedicated finishing steps:
- Precision Rotary Straightening: Before grinding, bars undergo multi-roll rotary straightening to eliminate residual forging or rolling bow. Straight bar stock eliminates low-frequency vibration in hydrodynamic bar feeders (
1,000–3,000 mm / 39.4"–118.1"channels) at high spindle speeds. - Chamfered & Deburred Ends: Abrasive saw-cut ends leave sharp titanium burrs that shred polyurethane feed-tube liners and jam collet fingers. We chamfer and deburr bar ends so automatic bar loaders transition seamlessly from bar to bar.
- Single Heat Lot Consistency: Titanium chip breaking and tool wear are highly sensitive to minor shifts in oxygen and iron content between different ingot melts. Supplying your batch from a Single Heat Lot ensures your Swiss lathe’s programmed feeds, speeds, and tool-life counters remain stable across the entire production run.
Calculate Your Tolerance Band & Request a Quote
Verify the exact unilateral negative tolerance limits for your diameter in our Tolerance Calculator, then send us your diameter, tolerance class (h6 / h7 / h8 / h9), cut length, and quantity requirements.