Custom CNC Turning for 316 Stainless Steel Bushings Used in Marine Equipment

This 316 stainless steel bushing was custom machined for marine equipment and supplied to a customer in the United States.

The part measures approximately 48 × 20 mm, with a large central bore, stepped outside diameters and a wider base. Most of the geometry shares the same centerline, so CNC turning and internal boring provide a direct way to produce the part without unnecessary secondary machining.

The order was approximately 1,000 pieces. The customer drawing specifies dimensional tolerances within ±0.05 mm, together with a Ra 1.6 surface finish.

There is nothing overly complicated about the machining route. The job is about producing the bore, outside profile and specified finish consistently across the full production run.

Project Details

The Geometry Keeps This Part on the Lathe

The component is built almost entirely around one rotational axis.

Its outside diameter changes through several steps before reaching the wider base, while the bore runs through the center of the bushing. These are natural turning features.

External turning establishes the outside profile and shoulders, while boring produces the internal diameter according to the customer drawing.

Keeping these operations on the lathe avoids setups that add no value to the part. It also gives us a straightforward production route for approximately 1,000 pieces.

For custom CNC turned parts, that is often preferable to making the machining process more complicated than the geometry requires.

The Bore Matters More Than the Part's Simple Appearance

At first glance, this looks like a relatively simple stainless steel turned component.

For a bushing, however, the internal diameter is one of the features that deserves closer attention. Depending on the final assembly, the bore may locate around or interface with another component in the marine equipment.

Its diameter therefore cannot be considered separately from the outside profile and shoulder positions.

Because the bore and OD share a common axis, CNC turning and boring allow the main internal and external features to be planned around the same rotational reference.

The specified dimensional tolerance is within approximately ±0.05 mm. We treat that as the drawing requirement it is, without presenting it as an unusually tight tolerance.

Ra 1.6 Starts at the Cutting Tool

The customer also calls for a Ra 1.6 machined surface finish.

This requirement cannot be reduced to a final visual check.

Tool condition, feed rate, cutting parameters and the finishing pass all influence the surface left by the turning tool. A diameter may measure correctly while its surface roughness still falls outside the specification.

The Ra 1.6 requirement is therefore considered when planning the machining conditions, particularly for the finishing passes.

For a CNC machined bushing, this can be especially relevant on surfaces that work with mating components. The requirement comes from the customer's drawing, so the machining process needs to reproduce it rather than simply make the part look smooth.

Batch Turning in 316 Stainless Steel

The specified material is 316 stainless steel.

Its corrosion resistance makes it a common choice for components used in marine and other demanding environments. From the machining side, 316 also requires sensible cutting conditions and attention to tool wear.

That becomes more relevant over a 1,000-piece order.

As a cutting edge wears, the change may begin to show in a turned diameter, bore or surface finish. Relevant dimensions and surface condition are therefore checked during the production run rather than waiting until every part has been completed.

A stable process is particularly valuable here because the customer needs repeat parts, not just one successful sample.

Made to the Customer's Drawing

This bushing is not a standard off-the-shelf item.

The customer drawing defines the 316 stainless steel material, internal bore, outside geometry, dimensional tolerances and Ra 1.6 finish. Those requirements determine how we plan the job.

The production route is relatively short:

Material Preparation → CNC Turning → Internal Boring → Finish Turning → Deburring → Inspection → Packing

Other turned parts may need threads, grooves, drilled holes or secondary milling. This one does not.

That is the point of made-to-drawing CNC turning: the process follows the component rather than forcing every customer part through the same sequence.

From the First Approved Parts to 1,000 Pieces

Once the initial setup is confirmed, attention shifts from proving the geometry to maintaining it.

During production, tool condition and relevant dimensions are monitored so that gradual changes can be corrected before they affect a larger portion of the batch.

This applies to the bore and outside dimensions, but also to the specified machined finish.

For repeat CNC lathe machining, consistency comes from controlling the process while the parts are being made—not from sorting good and bad parts at the end.

That is particularly relevant when a customer is sourcing hundreds or thousands of components from the same drawing.

Custom CNC Turning Services for Bushings and Turned Parts

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

Our turning work includes bushings, sleeves, shafts, pins, spacers, threaded components and other custom CNC turned parts. Depending on the design, machining can include external turning, internal boring, drilling, grooving and threading. Milling can be added when the drawing contains features that cannot be produced on the turning axis.

We machine 316 and 303 stainless steel, aluminum, brass and other specified materials for marine equipment, automation systems, medical devices, electronics and other industrial applications.

Projects can range from prototypes to repeat batch production. Before quotation, we review the drawing, material, tolerances, surface finish and required quantity so that the machining route reflects the actual part.

Need a Custom CNC Turned Bushing?

This project is a good example of what custom CNC turning often looks like in practice.

The part itself is straightforward: a 48 × 20 mm 316 stainless steel bushing produced by turning and internal boring. What makes the drawing specific are the dimensions, ±0.05 mm tolerance requirements and Ra 1.6 machined finish, followed by the need to repeat those requirements across approximately 1,000 pieces.

If you are sourcing a similar custom stainless steel bushing, CNC turned bushing or made-to-drawing lathe part, send us your 2D/3D files together with the material, quantity, tolerances and surface requirements. We can review the drawing and quote the machining process that fits the part.