Swiss-type turning handles small-diameter, high-precision components that a center-lathe struggles to hold in one setup. Buyers frequently hit concentricity, thread, and surface-finish problems on parts under 12mm in diameter. What follows is a practical checklist to run through before releasing an RFQ.
What Swiss-type turning tolerance means
A ±0.01mm callout on a 6mm shaft asks a lot of a standard center-lathe. The Swiss-type setup grips the workpiece at a guide bushing while the tool cuts from the side, keeping concentricity tight across two or three diameters. Long, thin features with a threaded end are where deflection and out-of-round usually show up on lesser machines.
For custom pins, threaded studs, and stainless-steel bushings, ask whether the shop runs thread-rolling or thread-cutting. Request a CMM first-article report and specify a thread-gauge check at the micro-geometry level. Pitch drift is something a visual walk-through will not catch, and it becomes visible only under a gauge or a profile projector.
Why Swiss-type turning suits small shafts
Material choice changes the machine setup considerably. Brass and copper sleeve components turn at higher feed rates and produce cleaner threads. 303 stainless and bronze bushings need slower passes to keep burr at the parting line under control. If your drawing specifies Ra 0.8 or better, confirm the program includes a single-point finishing pass rather than relying on the rough cut alone.
Weeda Precision runs drawing-based Swiss-type turning from prototypes through batch production, covering multi-diameter shafts, knurled pins, and brass insert nuts. On annual volumes above 5,000 pieces the parts ship in desiccant-lined cartons with a per-lot dimensional and surface-finish report attached, so the receiving team can verify before the batch enters stock.
Mark your drawing with the critical tolerance callout, state the thread class, and request a first-article inspection report. That small edit avoids a revision cycle and shortens lead time on the opening batch.