Multi-spindle Turning

Multi-spindle turning uses multiple synchronized spindles to machine bar stock in parallel, delivering tight-tolerance turned parts at very high production rates.

Overview

Multi-spindle turning uses cam-driven or CNC multi-spindle lathes (screw machines) to machine bar stock in several stations at once. Each spindle performs a different operation in parallel—facing, turning, drilling, threading—so a finished part drops every spindle index. This process excels at small to medium-sized, rotational parts with repeatable features and high annual volumes.

You should choose multi-spindle turning when you need millions to tens of thousands of parts with consistent diameters, short cycles, and automotive-grade repeatability. It handles most free-machining metals well and can hold tight tolerances on diameters and critical lengths. Tradeoffs: higher setup and tooling costs, less flexibility for frequent design changes, and limited suitability for long, slender, or highly complex geometries. Once dialed in, it delivers very low per-part cost and extremely stable quality for the right kind of turned component.

Common Materials

  • Aluminum 6061
  • Brass C360
  • Steel 12L14
  • Steel 1018
  • Stainless Steel 303
  • Copper

Tolerances

±0.0005" to ±0.002"

Applications

  • High-volume screws and fasteners
  • Hydraulic and pneumatic fittings
  • Bushings and spacers
  • Automotive shafts and pins
  • Standoffs and threaded inserts
  • Valve and fuel system components

When to Choose Multi-spindle Turning

Use multi-spindle turning for simple to moderately complex rotational parts where you need very high volumes, tight repeatability, and low piece-part cost. It’s ideal when part geometry fits bar-fed production and the design is stable enough to justify higher setup and tooling investment.

vs 2-Axis CNC Turning

Choose multi-spindle turning when you need much higher throughput and lower unit cost on stable, repeatable geometries. Once set up, a multi-spindle can outproduce multiple 2-axis CNC lathes on simple fittings, bushings, and fasteners, as long as you are not making frequent design changes.

vs Manual Lathe

Multi-spindle turning is far better when you move beyond prototype or very low-volume work. Use it when part counts justify automation and you need consistent, statistically controlled quality rather than operator-dependent results.

vs Mill-turn (Live Tooling)

Pick multi-spindle turning when parts are predominantly turned features with limited or simple cross-holes or flats, and volume is high. Mill-turn is more flexible for complex prismatic and off-axis features, but multi-spindle delivers lower cycle time and cost on straightforward turned parts in large runs.

vs Swiss Turning

Choose multi-spindle turning over Swiss when parts are relatively short and rigid, and you need extreme throughput rather than support for long, slender geometries. Swiss is better for very small, long parts; multi-spindle is more cost-effective for compact components produced in big volumes.

vs Manual Lathe

Use multi-spindle turning once your demand moves beyond custom or repair work into repeat production. It eliminates manual handling, reduces cycle time per part, and provides better dimensional consistency for large orders.

Design Considerations

  • Design parts to be fully machinable from bar stock, avoiding features that require gripping on complex shapes or castings
  • Keep part length-to-diameter ratio low to maintain rigidity and reduce chatter on high-speed multi-spindle machines
  • Standardize diameters, threads, and chamfers to use off-the-shelf tooling and reduce custom tool costs
  • Avoid deep cross-holes and complex off-axis features that require extra stations or secondary operations
  • Call out realistic tolerances and surface finishes; reserve the tightest specs only for true functional needs to keep cycle times down
  • Provide clear thread specs (form, class, gage) and any critical leak-path or sealing surfaces so the shop can choose appropriate tooling and inspection