ISO 9001 & AS9100 Certified CNC Grinding Facility
CNC Grinding Services
CNC grinding is the precision finishing process engineers turn to when milling or turning cannot deliver the tolerances or surface quality their parts demand.
Whether you need flatness within 0.005 mm on a hardened die plate, roundness to 0.001 mm on a bearing shaft, or a surface finish below Ra 0.4 µm on a medical component, CNC grinding services provide the accuracy that subtractive manufacturing alone cannot guarantee.
±0.0005″
Tolerance (typical)
5–10 days
Standard lead time
Free review
On every CAD file
MOQ 1
Prototype to production
CNC Grinding Fundamentals
What Is CNC Grinding?
CNC grinding uses a rotating abrasive wheel to remove material from a workpiece with extreme precision. Unlike milling or turning, which use cutting tools with defined edges, grinding uses thousands of microscopic abrasive grains to shear away material in very small increments. This makes grinding ideal for achieving tight dimensional tolerances, excellent surface finishes, and accurate geometry on hard or heat-treated materials.
The process is typically a secondary operation. A part is first machined close to final dimensions through CNC milling or CNC turning, then hardened if needed, and finally ground to achieve the precision that earlier processes cannot reliably hold. Grinding can remove as little as a few microns per pass, allowing operators to dial in dimensions that would be impossible with conventional cutting tools.
Abrasive Precision
Microscopic grains for micron-level material removal
Tight Tolerances
Ideal for hardened materials & high-accuracy dimensions
Superior Finishes
Excellent surface quality down to Ra 0.1 µm
Secondary Operation
Perfect for post-heat-treatment finishing
Precision Finishing Process
Achieves tolerances and surface finishes impossible with conventional cutting tools.
Grinding Capabilities
Our CNC Grinding Capabilities
Baetro operates a dedicated grinding department from our ISO 9001-certified facility, offering surface, cylindrical, and centerless grinding with precision quality control.
Advanced Equipment
Precision Grinding Equipment
We utilize CNC surface grinders, universal cylindrical (OD/ID) grinders, and through-feed centerless machines, maintained for ISO 9001 consistency.
- Surface: High-precision flat surface finishing.
- Cylindrical: OD and ID grinding capabilities.
- Centerless: Efficient through-feed grinding.
- Maintenance: Regular calibration for accuracy.
Quality Assurance
Rigorous Quality Control
Every part undergoes CMM verification and surface roughness testing. We provide full inspection reports with dimensional data and material certificates.
- Verification: CMM dimensional inspection.
- Testing: Surface roughness (Ra) confirmation.
- Reporting: Full inspection reports included.
- Traceability: Material certificates compiled.
Process Expertise
Expert Process Control
Our experts manage thermal distortion, wheel dressing, and coolant concentration to prevent micron-level drift, ensuring tight-tolerance accuracy.
- Thermal: Distortion management systems.
- Optimization: Precise wheel dressing intervals.
- Control: Coolant concentration monitoring.
- Result: Consistent output, zero scrap.
Procurement confidence
Why Choose Baetro for CNC Grinding Services?
Most buyers encounter two options: marketplaces that treat grinding as an afterthought, or small shops that cannot handle multi-process projects. Baetro is different.
Direct Manufacturer
Work directly with the engineers and operators who will make your parts. No intermediaries, no opaque supplier networks.
Free Engineering Review
Upload your CAD file. We review grindability, stock allowances, fixture access, and process sequence before quoting.
Multi-Process Integration
Milling, turning, heat treatment, grinding, and finishing under one roof. One PO, one point of contact.
No Minimum Order Quantity
Order one prototype or ten thousand parts. Same quality controls and traceability at any volume.
Instant Online Quotes
Upload STEP or IGES, select material and finish, get pricing and lead time in under 60 seconds.
Consultative Approach
If a design would be more economical to finish-machine rather than grind, we will tell you upfront.
Material library
Materials We Grind
Grinding is not limited to soft or easy-to-machine metals. In fact, its greatest advantage appears on materials that challenge conventional cutting tools.
Hardened Steels & Tool Steels
Hardened steels above 45 HRC quickly dulls end mills and inserts — grinding wheels cut it efficiently. Tool steels (A2, D2, S7), alloy steels (4140, 4340), and case-hardened components all require grinding after heat treatment to achieve final dimensions.
Applications: dies, molds, shafts, gears, and wear-resistant components requiring post-heat-treatment precision.
Stainless Steels & Super-Hard Materials
Stainless steels including 304 and 316 are regularly ground for medical, marine, and food-processing applications. Stainless work-hardens during machining, making grinding an attractive alternative for tight-tolerance features.
Carbide & ceramics require diamond or CBN grinding wheels. These super-hard materials are used in cutting tools, wear components, and specialized industrial parts.
Material
Hardened Steel
A2, D2, S7, 4140, 4340, and case-hardened grades. Ideal for post-heat-treatment finishing.
Material
Stainless Steel
304, 316 grades for medical, marine, and food-processing applications requiring tight tolerances.
Material
Carbide & Ceramics
Tungsten carbide and technical ceramics requiring diamond or CBN grinding wheels.
Material
Aluminum & Soft Metals
Ground when exceptional flatness or surface finish is required. Typically post-machining finishing.
Post-processing
Surface Finishes for CNC Ground Parts
Parts ship with an as-ground finish by default, but we offer additional surface treatments so your components arrive ready for assembly or end-use.
| Finish | Description | Best For |
|---|---|---|
| As ground | Fine ground surface, Ra 0.4–0.8 µm, visible grind lines | Precision functional surfaces, bearing fits, sealing faces |
| Superfinished | Ultra-smooth surface, Ra 0.1–0.2 µm, mirror-like appearance | High-performance bearings, hydraulic spools, critical seals |
| Bead blasted (post-grinding) | Uniform matte texture that softens grind lines | Cosmetic parts, preparation for coating, reduced reflectivity |
| Black oxide | Mild corrosion resistance, reduced reflectivity, no dimensional change | Steel tooling, fasteners, functional hardware, ground components |
| Nickel plating (post-grinding) | Corrosion and wear protection with good dimensional stability | Ground steel components requiring protection and appearance |
| Passivation (stainless) | Removes surface iron, restores corrosion resistance after grinding | Medical implants, food-processing equipment, aerospace parts |
Engineering data
CNC Grinding Tolerances & Surface Finish
Grinding exists because other processes hit their limits. Where CNC machining typically achieves ±0.025 mm tolerances and Ra 1.6 µm surface finishes, grinding pushes well beyond those thresholds.
Grinding Tolerance & Finish Capabilities
| Process | Typical Tolerance | Surface Finish (Ra) | Best For |
|---|---|---|---|
| CNC milling / turning | ±0.025 mm | 0.8–6.3 µm | General geometry, soft materials |
| CNC surface grinding | ±0.005 mm (flatness) | 0.4–0.8 µm | Flat surfaces, post-heat-treat finishing |
| CNC cylindrical grinding | ±0.001 mm | 0.2–0.4 µm | Roundness, concentricity, bearing fits |
| CNC centerless grinding | ±0.0025 mm (diameter) | 0.4–0.8 µm | High-volume cylindrical parts |
These tolerances are not theoretical maximums — they are the standards we hold on production parts every day. Achieving them requires wheel selection, dressing parameters, coolant delivery, and thermal management.
Surface Finish & Process Control
- Wheel grit size & feed rate: Coarse grits remove material faster but leave rougher surfaces. Fine grits and slow feeds produce mirror-like finishes.
- Typical grinding range: Ra 0.2–0.8 µm achievable on production parts without secondary polishing or lapping.
- Critical applications: Seals, bearings, optical housings, and medical components where Ra 0.4 µm or finer is required.
- Process monitoring: Our operators monitor in-process dimensions and adjust parameters to prevent drift across long production runs.
Applications
Industries We Serve with CNC Grinding
CNC grinding services serve every industry where precision mechanical components operate under load, at speed, or in critical safety environments.
Industry
Aerospace & Defense
Engine shafts, landing gear actuators, turbine blade roots, and hydraulic spool valves. Tolerances of ±0.001 mm with finishes below Ra 0.4 µm.
Industry
Automotive
Camshafts, crankshafts, transmission shafts, steering components, valve stems, and bearing rollers for engines and EV drivetrains.
Industry
Medical Devices
Orthopedic implants, surgical instruments, and diagnostic equipment requiring biocompatible materials and exceptional surface finishes.
Industry
Mold & Die / Tooling
Injection mold components, stamping dies, precision bearings, hydraulic valves, and machine tool ways requiring flatness and parallelism.
Industry
Industrial Equipment
Hydraulic valve spools, measurement fixtures, bearing journals, and wear-resistant components for heavy machinery and automation.
Industry
Power Generation
Turbine shafts, generator components, and precision rotating parts requiring concentricity and high-cycle fatigue resistance.
Prototypes & Production
Types of CNC Grinding We Offer
Baetro provides three core grinding processes, each suited to different part geometries, volumes, and precision requirements. Choosing the right process affects tolerance capability, lead time, and cost.
CNC Surface Grinding
Flat, smooth surfaces with tight control over thickness, parallelism, and surface finish. The workpiece is held stationary while a rotating grinding wheel passes across it.
- Best for: die plates, fixture bases, mold inserts, and sealing surfaces
- Capability: flatness within 0.005 mm, Ra 0.4–0.8 µm finish
- Key advantage: corrects distortion after heat treatment in a single setup
- Typical applications: post-hardening finishing, precision flat components
CNC Cylindrical Grinding
Outer and inner diameters of round parts with excellent control over roundness, concentricity, and diameter consistency. The workpiece rotates between centers or in a chuck.
- Best for: shafts, bearing races, hydraulic cylinders, spindle components
- Capability: OD & ID grinding, plunge and traverse methods
- Key advantage: delivers final precision after CNC machining
- Typical applications: bearing journals, hydraulic bores, precision shafts
CNC Centerless Grinding
Cylindrical parts processed without centers, chucks, or fixtures. The workpiece rests on a support blade between a grinding wheel and a regulating wheel.
- Best for: pins, fasteners, linear shafts, long bars, and tubes
- Capability: ±0.0025 mm diameter consistency, 2–3× faster throughput
- Key advantage: continuous-feed eliminates individual part setup time
- Typical applications: high-volume cylindrical components, stepped diameters
Process selection
When to Specify Grinding Instead of Machining
Not every part needs grinding. Understanding when grinding is necessary — and when it is overkill — helps you design for manufacturability and control cost.
After Heat Treatment
Hardening distorts dimensions and leaves scale on surfaces. Leave 0.1–0.3 mm stock per surface. Grinding restores precision after heat treatment.
Tighter Than ±0.025 mm
Milling can achieve tight tolerances, but grinding holds them reliably across production runs. For ±0.01 mm or better, grinding is the safer choice.
Surface Finish Below Ra 0.8 µm
Grinding produces Ra 0.4 µm or finer as routine output. Sealing surfaces, bearing fits, and optical interfaces require grinding.
Material Harder Than 45 HRC
Cutting tools lose edge life rapidly on hardened steel. Grinding wheels cut efficiently at 60 HRC and above. Plan grinding as the finishing operation.
If you are unsure whether your part requires grinding, upload your drawing for a free DFM review. Our engineers will recommend the most efficient process sequence for your tolerance, material, and volume requirements.
Cost & Lead Time
CNC Grinding Cost & Lead Time
Standard lead time for CNC grinding services at Baetro is 5–10 days from order confirmation to shipment. Rush service is available for projects with urgent deadlines. Parts ship globally with full documentation and tracking.
- Tolerance Requirements Tighter tolerances require slower feed rates, more frequent wheel dressing, and longer inspection cycles. A part with ±0.001 mm tolerance costs more than ±0.01 mm.
- Surface Finish Specification Achieving Ra 0.2 µm requires finer wheels, slower passes, and more careful coolant control than Ra 0.8 µm. The difference can add 20–40% to cycle time.
- Material Hardness Grinding hardened tool steel at 60 HRC wears wheels faster than grinding annealed 4140 at 20 HRC. Wheel consumption and dressing frequency affect cost.
- Part Geometry & Fixturing Simple flat plates grind quickly. Complex profiles, internal bores, or parts requiring custom fixtures take longer.
For an exact quote on your specific part, upload your CAD file and select your material, finish, and quantity. You will see pricing and lead time instantly — no sales call required.
FAQ
Frequently Asked Questions
Answers to common questions about CNC grinding tolerances, surface finishes, hardened materials, lead times, and quality control.
What tolerances can CNC grinding hold?
CNC grinding routinely achieves tolerances of ±0.001 mm on cylindrical features and flatness within 0.005 mm on surface-ground components. Ultra-precision grinding can reach ±0.0002 mm (±0.2 µm) on specialized equipment. The practical limit depends on part size, material, geometry, and the specific grinding process used.
What surface finish can grinding achieve?
Standard CNC grinding produces surface finishes in the Ra 0.4–0.8 µm range. Fine grinding with appropriate wheels and parameters can achieve Ra 0.2 µm. For context, CNC milling typically delivers Ra 0.8–6.3 µm, and standard as-machined surfaces are around Ra 3.2 µm. Grinding is the most practical way to achieve sub-micron surface finishes without secondary polishing or lapping.
Can you grind hardened steel?
Yes. Grinding is actually the preferred finishing process for hardened steel above 45 HRC. Cutting tools wear rapidly on hard material, but grinding wheels cut efficiently at 60 HRC and above. Common ground hardened materials include tool steels (A2, D2, S7), alloy steels (4140, 4340), and stainless steels (17-4 PH, 440C).
How does centerless grinding differ from cylindrical grinding?
Cylindrical grinding holds the workpiece between centers or in a chuck, providing excellent control over concentricity and alignment between multiple diameters. Centerless grinding supports the part on a blade between two wheels, eliminating setup time for individual pieces and enabling much higher throughput. Choose cylindrical grinding for complex shafts with multiple diameters; choose centerless grinding for high-volume simple cylindrical parts.
What is the typical lead time for CNC grinding services?
Standard lead time is 5–10 days from order confirmation to shipment. Simple surface grinding on small quantities may ship in 3–5 days. Complex cylindrical grinding with tight tolerances or large volumes may require the full 10-day window. Rush service is available — contact us with your deadline and we will confirm feasibility.
Do you offer grinding as a standalone service or only with machining?
Both. We accept standalone grinding work on customer-supplied blanks, and we provide integrated multi-process manufacturing where we machine, heat-treat, grind, and finish the part in sequence. The integrated approach reduces handling, shortens lead time, and ensures consistent quality across process steps.
What inspection reports do you provide for ground parts?
Every shipment includes a full inspection report documenting dimensional measurements, surface roughness values, and material certifications. For tight-tolerance parts, we provide CMM inspection data showing measured values against drawing dimensions. All reports are included at no additional cost.
Is there a minimum order quantity for CNC grinding?
No. Baetro has no minimum order quantity. We will grind one prototype part or ten thousand production parts. Our instant quoting system provides pricing for any quantity — enter your desired quantity and see the per-part price immediately.
Quote-ready manufacturing
Get Started with Your CNC Grinding Project
CNC grinding services close the precision gap that milling and turning cannot bridge. When your parts require tight tolerances, fine surface finishes, or hard-material capability, grinding delivers the accuracy that keeps assemblies fitting, seals sealing, and machines running.
At Baetro, we combine dedicated grinding equipment, experienced operators, and engineering review on every quote to ensure your parts meet specification the first time. From our ISO-certified facility in Qingdao, we ship precision-ground components to customers across North America, Europe, and Asia, backed by full inspection reports and dedicated project managers who keep you informed at every step.
See your exact price and lead time in under 60 seconds. No minimum order quantity. ISO 9001 & AS9100 certified.
Not ready to upload a file? Contact our engineers to discuss your project, review material options, or get guidance on tolerance and finish requirements.