Custom 304 Stainless Steel CNC Turned Parts for Rail Transit Equipment

This small 304 stainless steel turned part was produced for a rail transit equipment project and shipped to the Czech Republic. The part is only about 35 × 10 mm, but the order quantity was around 10,000 pieces, so the focus was less on machining complexity and more on keeping the production run stable.

The component is made to the customer's drawing. Most features are rotational, including the long outside diameter, several stepped sections and narrow grooves. One end has a clearly defined diamond knurl.

CNC turning is a natural choice for this geometry. The important part is making sure the dimensions, knurl and edge condition remain consistent as production moves from the first pieces into thousands.

Project Details

The Part Is Small, and the Turning Route Is Straightforward

There is no reason to make this component sound more complicated than it is.

Most of the shape runs along one centerline, which makes CNC lathe machining a sensible production route. The main outside diameter can be turned first, followed by the smaller steps, grooves and end features. The diamond knurl is formed as part of the turning process before parting and deburring.

A typical route is:

CNC Turning → Grooving → Knurling → Parting → Deburring → Inspection

For 10,000 pieces, a straightforward process is an advantage. Fewer setups mean less handling and a shorter cycle, while also reducing the number of places where variation can enter the job.

The Knurl Needs Attention After the First Few Hundred Parts

The knurled end is a small feature, but it is easy to notice.

On the first few samples, getting a clean diamond pattern is not particularly difficult. During a longer run, the concern shifts to what happens as the tooling accumulates production time.

If the knurl starts losing definition, the change may be gradual rather than obvious from one part to the next. Tool condition therefore needs to be watched during the run instead of relying only on inspection after all 10,000 pieces are finished.

The same thinking applies to the turned diameters and grooves. A stable first article is important, but it is only the beginning of the job.

Working with 304 Stainless Steel in a 10,000-Piece Run

The drawing specifies 304 stainless steel, so we plan the machining around that requirement.

With this quantity, cutting conditions and tool life become more important than they would be for a small prototype order. Tool wear can gradually influence diameter and surface condition, while chip control also needs to remain manageable through continuous production.

This is where stainless steel CNC turning becomes a production problem rather than simply a machining problem.

The objective is not to chase the tightest possible tolerance on every dimension. It is to keep the dimensions specified on the customer's drawing stable throughout the batch.

Small Burrs Are Not So Small on a 10 mm Part

Another detail we watch is the edge condition.

The component has several stepped transitions, grooves and a part-off end. These areas can leave small burrs after turning. On a part with a maximum diameter of only around 10 mm, those burrs can be significant relative to the surrounding features.

They need to be removed without unnecessarily rounding an edge that the drawing expects to remain defined.

It sounds like a minor operation, but on small precision turned parts, deburring is often one of those details that separates a clean production part from one that still needs work when it reaches the customer.

Production Checks Follow the Drawing

We do not apply the same inspection effort to every dimension simply because the order contains 10,000 pieces.

The drawing tells us which features matter.

Once those dimensions are identified, they can be checked during production at appropriate intervals. If tool wear starts moving a diameter or groove away from its expected value, the process can be corrected before a large number of parts are affected.

This is more practical for volume CNC turning than producing thousands of pieces first and depending entirely on final inspection.

For repeat orders, the same process information also gives us a better starting point the next time the part comes back into production.

Made-to-Drawing CNC Turning for Stainless Steel Parts

YS Precision provides custom CNC turning services for components manufactured from customer 2D drawings and 3D models.

Our turning work covers stainless steel, aluminum, brass and other metals, with processes including CNC lathe machining, precision turning, grooving, knurling, threading, drilling, Swiss-type CNC turning and turn-mill machining where the part geometry requires them.

For small components like this one, we look at the drawing, quantity and feature arrangement before deciding on the machining route. A conventional CNC lathe may be the simplest choice; for other small precision parts or different geometries, Swiss-type machining may be more suitable.

The goal is not to put every part on the most sophisticated machine available. It is to use a process that makes sense for the drawing and the production quantity.

Sourcing Similar Stainless Steel Turned Parts?

This Czech rail transit project involved a relatively simple part, but a meaningful production quantity: around 10,000 pieces of 304 stainless steel hardware made to the customer's drawing.

That makes repeatability more important than complexity.

If you are sourcing custom stainless steel CNC turned parts, send us the drawing together with the material grade, quantity, tolerances and any specific requirements for knurling or surface condition. We can review the part and quote the machining based on the actual drawing requirements.