Combining CNC Turning and Centerless Grinding: Optimizing Production of Precision Parts

CNC turning and centerless grinding accomplish different goals, but they complement one another perfectly. Turning shapes the part by removing bulk material and cutting features like shoulders, grooves, or tapers. Centerless grinding then refines the diameter, straightness, and finish, producing a final part with exceptional dimensional accuracy.



Using the two processes together allows manufacturers to:

• Rough or semi-finish turn a stainless bar
• Grind the final diameter to precise tolerances
• Achieve straightness, roundness, and finish not possible through turning alone
• Deliver predictable quality on repeat orders

At Action Stainless, this integrated workflow gives customers access to a complete machining and finishing process that supports both simple and complex stainless components.

CNC turning uses a lathe to rotate the stainless bar while cutting tools remove material. This process is ideal for producing:

• Shoulders
• Steps
• Grooves
• Threaded sections
• Tapers
• Complex profiles

Turning is highly efficient for shaping the outer profile of the bar and achieving accurate geometry. It’s particularly effective at removing large amounts of material quickly, bringing a part close to its final diameter.

However, even the best CNC machines have limitations when it comes to:



• Long, slender shafts
• Extremely tight diameter tolerances
• Very fine surface finishes
• Correcting roundness or straightness issues in bar stock

These are areas where centerless grinding completes the process.

Centerless grinding offers full-length support for stainless bars by rotating them between a grinding wheel and a regulating wheel while supported on a rest blade. This method produces exceptional control over:

• Final diameter
• Straightness
• Roundness
• Surface finish



The process removes small amounts of material but does so in a way that eliminates deflection and produces highly consistent results. Centerless grinding is often the final step before assembly or polishing, especially when components require tight tolerances.

When CNC turning and centerless grinding are used together, the result is a more efficient and predictable workflow. Turning establishes the part’s overall geometry, while grinding perfects the final size and finish. This hybrid approach offers several important benefits:

Turning removes most of the material quickly. Grinding then finishes the part to size with minimal removal, shortening the overall cycle time compared to grinding from full diameter.

Turning prepares the geometry; grinding refines the final diameter. The combination provides accuracy that neither process achieves alone with the same efficiency.

Even well-turned shafts may have minor runout or taper. Grinding corrects these issues and produces consistent roundness from end to end.

Grinding produces a finer, more uniform surface finish, reducing friction and improving performance in seals, bearings, and rotating assemblies.

Since most material removal occurs during turning, grinding wheels last longer and operate more consistently.

Manufacturers who switch from single-process machining to a hybrid process often achieve better part quality, reduced scrap, and lower overall production cost.

Many stainless steel parts perform better when both processes are used. Common examples include:

• Hydraulic cylinder rods
• Linear motion shafts
• Pump shafts
• Motor drive shafts
• Precision pins and dowels
• Valve stems
• Structural or marine shafts
• OEM components requiring tight tolerances

In these applications, diameter consistency, straightness, and surface condition directly affect pressure sealing, motion accuracy, and part longevity.

Bars are cut to length using in-house cutting equipment before entering CNC machining. Good preparation reduces vibration and improves accuracy in later steps.

Parts are turned to near-final diameter, leaving a controlled allowance for grinding. Features such as shoulders, grooves, or precision lengths are added during this stage.

The turned bar moves directly into centerless grinding. Grinding refines the final diameter, straightens the bar if needed, and improves surface finish.

For components requiring a sanitary, reflective, or aesthetic surface, polishing can follow grinding for enhanced finish quality.

Parts are checked for diameter, finish, straightness, and geometry before shipment or additional machining.



This integrated process maintains continuity and control, preventing quality differences that occur when machining and grinding are spread across multiple vendors.

This comparison shows why many stainless components require both turning and grinding to meet functional requirements.

Precision is not just about meeting numerical tolerances. It's about reliability during operation. A shaft may measure correctly but still cause issues if it lacks straightness or surface consistency. Combining turning and grinding eliminates these weaknesses, producing parts that perform better under load, rotation, or pressure.

By starting with CNC turning and finishing with centerless grinding, manufacturers achieve:

• Greater component stability
• Longer seal and bearing life
• Improved assembly consistency
• Reduced vibration in rotating systems
• Better corrosion resistance due to smoother surfaces

Action Stainless customers rely on this combined process to maintain quality across repeat orders and performance-critical applications.

The turn-and-grind method is widely used in industries such as:

• Hydraulics - where straightness and finish influence seal integrity
• Food processing - requiring sanitary, easy-to-clean surfaces
• Marine and offshore - demanding corrosion-resistant, dimensionally stable stainless
• OEM machinery - requiring repeatable production quality
• Energy and chemical systems - needing reliable stainless components under pressure

Because Action Stainless provides both turning and grinding in one facility, these industries benefit from shorter lead times, consistent results, and direct control over part accuracy.

Having CNC turning and centerless grinding in-house provides a major advantage for customers who need precision stainless components. Instead of coordinating multiple vendors or managing separate timelines, customers receive a seamless workflow with predictable results.

This integration means:

• Less handling
• Shorter production cycles
• Better consistency across batches
• Single-source documentation and MTRs
• Improved communication throughout production

The result is stainless parts that are not only accurate but also manufactured efficiently and consistently from order to order.

When your stainless components require both dimensional accuracy and refined surface quality, combining CNC turning and centerless grinding delivers the best results. Action Stainless provides these services under one roof, ensuring precision, efficiency, and consistency from the first cut to the final finish.

To request a quote or review machining and grinding options, visit https://www.actionstainless.com and connect with the team for support on your next precision stainless project.