CNC machining steel is a fundamental operation in modern manufacturing, serving industries such as automotive, aerospace, oil & gas, defense, medical devices, and industrial machinery. This guide explores everything you need to know about CNC machining steel — from material grades and machinability to tooling, parameters, and expert tips.
What Is CNC Machining Steel?
Choosing the right steel for precision CNC machining is the first step toward reliable and efficient product development. But what exactly does CNC machining steel involve?
CNC machining steel refers to the use of computer-controlled machines to cut, drill, mill, and shape steel into precise components based on CAD models. Unlike manual machining, CNC (Computer Numerical Control) ensures tight tolerances, repeatability, and production efficiency—crucial for sectors that demand accuracy and strength.

Steel remains one of the most commonly machined materials due to its high tensile strength, durability, and cost-effectiveness. It’s ideal for both prototyping and end-use parts in structural, mechanical, and load-bearing roles.
Why Steel?
- Versatility: Available in multiple grades (carbon, alloy, stainless, tool steel) tailored for strength, hardness, and corrosion resistance.
- Performance: Supports high-speed machining and performs well under mechanical stress.
- Cost-Benefit: Balances strength and affordability, especially in medium to high-volume production runs.
How CNC Technology Enhances Steel Machining
With advanced software and high-performance tooling, CNC technology allows:
- Intricate geometries with minimal waste
- Repeatability for mass production of critical parts
- Efficient material removal with reduced cycle time
Whether you’re producing a gear shaft, engine bracket, or surgical instrument, CNC machining of steel ensures the precision and material properties necessary for demanding industries.
Common Types of Steel Used in CNC Machining
Not all steel is created equal—especially when it comes to CNC machining. Choosing the right type of steel determines how easily it machines, how it performs under stress, and how it resists corrosion and wear over time.
The main steel categories—carbon, alloy, stainless, and tool steel—each bring unique properties to the table. Here’s how they differ and when to use them:
Carbon Steels
These are the most basic and cost-effective steels. They’re commonly used in structural parts, fixtures, and low-stress components.
| Grade | Properties | Common Uses |
|---|---|---|
| 1018 | Good weldability, fair strength | General components, shafts |
| 1045 | Medium carbon, higher strength | Gears, pins, axles |
| 1144 | Free-machining, good surface finish | Machined parts needing tight tolerances |
Alloy Steels
These steels are alloyed with elements like chromium, molybdenum, and nickel for better strength, toughness, and wear resistance. Ideal for parts under mechanical stress.
| Grade | Properties | Common Uses |
|---|---|---|
| 4140 | High strength, fatigue resistance | Tooling, structural parts |
| 4340 | Very tough, good hardenability | Aircraft landing gear, shafts |
| 8620 | Good for case hardening | Gears, camshafts |

Stainless Steels
These corrosion-resistant steels are ideal for harsh or hygienic environments such as marine, medical, and food equipment.
| Grade | Properties | Common Uses |
|---|---|---|
| 303 | Easy to machine | Fasteners, fittings |
| 304 | Corrosion-resistant, weldable | Food processing equipment |
| 316 | Marine-grade corrosion resistance | Pumps, valves, surgical devices |
| 17-4PH | High strength + corrosion resistance | Aerospace, medical tools |
Tool Steels
Engineered for toughness, hardness, and wear resistance, these are used in tooling and high-wear applications.
| Grade | Properties | Common Uses |
|---|---|---|
| D2 | High wear resistance | Dies, punches |
| O1 | Easy to heat treat | Cutting tools |
| A2 | Good toughness, air hardening | Mold components |
| H13 | Hot work, thermal shock resistance | Injection molds, extrusion dies |
Each steel type is engineered to match specific project demands. Knowing your design and performance requirements is key to making the best selection for your CNC machining needs.
Key CNC Machining Operations for Steel
Steel’s strength and versatility make it ideal for a wide range of machining operations, from basic cuts to intricate detailing. Knowing the right operation for the job ensures part accuracy, surface quality, and cost-effectiveness.
CNC machines handle steel with precision through various subtractive techniques, each tailored for specific geometries and finishes.
Core CNC Operations for Steel
| Operation | Description | Best Used For |
|---|---|---|
| Turning | Rotates the workpiece while a cutting tool removes material | Shafts, bushings, round parts |
| Milling | Uses rotating multi-edge tools to cut away from a fixed block | Flat surfaces, pockets, contours |
| Drilling | Creates cylindrical holes with precise diameter and depth | Bolt holes, fluid channels |
| Tapping | Adds internal threads to pre-drilled holes | Assembly-ready parts |
| Boring | Enlarges and fine-tunes existing holes | Precision bores for bearing housings |
| Grinding | Removes small amounts of material for fine surface finish | High-precision fits, cosmetic finishes |
| Broaching | Pulls a toothed tool to cut complex internal shapes | Keyways, splines, internal gears |

Toolpath Strategy Matters
Choosing between climb milling and conventional milling, optimizing feed per tooth, and applying trochoidal milling paths for hard alloys all impact tool life and part quality. For high-carbon or hardened steel, slow and steady wins the race—lower cutting speeds with proper coolant ensure surface integrity and prevent premature wear.
In high-volume runs, combining operations in multi-axis or mill-turn machines increases efficiency. For instance, drilling and tapping can be done in one setup, reducing error and cycle time.
Mastering these operations not only enhances part accuracy but also extends tool life and reduces scrap—crucial in steel CNC machining where margins for error are tight and materials are tough.
Tooling Considerations for Steel Machining
Machining steel requires durable tooling strategies to overcome high cutting forces, potential work hardening, and heat generation. The wrong tool or setup can quickly degrade performance or even damage equipment.
The key to success lies in choosing appropriate tool materials, geometries, and coatings tailored for each steel grade and machining objective.
Tool Material Selection
| Tool Material | Benefits | Use Case |
|---|---|---|
| Carbide | High hardness and thermal resistance | High-speed finishing of alloy and stainless steels |
| High-Speed Steel (HSS) | Cost-effective, easy to resharpen | General-purpose or low-speed roughing |
| Cermet | Superior wear and heat resistance | Precision operations with long cycle times |

Tool Geometry Tips
- Positive Rake Angles: Reduce cutting force in stainless and work-hardened steels.
- Reinforced Cutting Edges: Prevent chipping in high-hardness alloys like 4140 and D2.
- Wiper Inserts: Improve surface finish without slowing feed rate.
Tool Coatings
| Coating | Properties | Best For |
|---|---|---|
| TiAlN | High heat resistance, oxidizes at 800°C+ | Dry machining and interrupted cuts |
| TiCN | Reduces friction, good wear resistance | Machining hard, abrasive steels |
| AlTiN | Thermal stability, hard oxide barrier | Stainless steel and hardened alloys |
Tool Life Management
To maximize tool longevity, always:
- Use toolpath simulation to eliminate unnecessary air cuts.
- Apply consistent cutting parameters matched to steel grade.
- Monitor wear via in-process inspection or tool breakage detection.
Smart tooling choices dramatically affect cycle time, part quality, and shop efficiency. In steel CNC machining—where materials push back—well-prepared tooling is your best ally.
Cutting Parameters
Steel machining demands precise control over cutting parameters to achieve balance between speed, accuracy, tool life, and surface integrity. Improper settings can lead to tool wear, excessive heat, and poor finish—especially in hard steels or stainless variants.

To maximize performance and efficiency, adjust your parameters based on material grade, tooling setup, and machine capability.
Recommended Cutting Parameters by Operation
| Parameter | Typical Range | Notes |
|---|---|---|
| Cutting Speed (Vc) | 60–180 m/min | Low speeds for hard alloys; high speeds for carbon steels |
| Feed Rate (f) | 0.05–0.3 mm/rev | Lower for finishing, higher for roughing |
| Depth of Cut | 0.1–0.5 mm (finishing) 1–3 mm (roughing) | Keep consistent to reduce load spikes |
| Spindle Speed (n) | Based on Vc = (1000 × Vc) / (π × D) | Calculate from cutting speed and tool diameter |
| Coolant | Flood coolant or mist | Essential for stainless/tool steels; improves tool life |
Fine-Tuning Tips
- Use constant surface speed (CSS) on lathes to maintain consistent cutting conditions across varying diameters.
- Apply trochoidal milling for deep pockets in tool steels to reduce tool stress.
- Minimize dwell time when machining stainless steels to avoid work hardening.
In CNC machining steel, the right cutting parameters don’t just ensure better part outcomes—they also extend tool life and reduce cycle times. Adjust carefully based on heat generation, chip evacuation, and tool wear feedback.
Surface Finishes for Machined Steel
Surface finish plays a critical role in the performance, appearance, and functional longevity of machined steel parts. Choosing the right finishing method ensures parts meet mechanical fit, aesthetic, and environmental requirements.
Common Finish Types & Their Applications
- As-machined (Ra 3.2–6.3 µm)
Ideal for functional prototypes or internal components where tight visual finish is not needed. - Grinding (Ra 0.2–0.8 µm)
Used for precision mating surfaces, bearing seats, and sealing faces requiring high flatness and smoothness. - Polishing
Delivers a mirror-like surface for cosmetic parts, medical tools, and consumer-facing components. - Black Oxide Coating
Adds light corrosion resistance and reduces glare—common in fasteners, tools, and interior enclosures. - Zinc/Nickel Plating
Offers enhanced corrosion protection and electrical continuity—ideal for outdoor or electrically conductive parts.
Choosing the Right Finish
| Finish Type | Ra (µm) | Typical Use |
|---|---|---|
| Machined | 3.2–6.3 | Prototypes, rough assemblies |
| Ground | 0.2–0.8 | Precision fits, sealing surfaces |
| Polished | <0.2 | Visual components, hygiene-critical parts |
| Black Oxide | Varies | Tools, fasteners, indoor corrosion protection |
| Zinc/Nickel Plating | Shiny finish | Outdoor protection, electrical parts |

Best Practices for Finishing
- Hold critical dimensions before applying finishing—coatings add thickness.
- Specify Ra or gloss level in technical drawings to ensure supplier clarity.
- Perform post-finish inspections with profilometry or CMM to verify results.
By selecting the right surface finish, you improve wear resistance, assembly fit, corrosion protection, and aesthetics—all without compromising the integrity of your machined steel parts.
Heat Treatment of Steel
Heat treatment is a critical step in the CNC machining process for steel, significantly affecting its mechanical properties, machinability, and performance in the final application. This process can be applied before or after machining, depending on the desired outcomes such as hardness, ductility, or dimensional stability.

Heat Treatment Before Machining
Pre-machining heat treatments prepare steel for easier and more precise cutting.
- Annealing – Softens steel by heating it and then slowly cooling it. This reduces internal stresses and makes the material easier to machine. It’s commonly used for tool steels like D2 or O1.
- Normalizing – Refines grain structure and enhances uniformity. Often applied to carbon and alloy steels to stabilize them before machining.
Heat Treatment After Machining
Post-machining heat treatments aim to enhance strength, toughness, and surface durability.
- Quenching & Tempering – Increases hardness and strength by heating steel, rapidly cooling it (quenching), and then reheating it to a moderate temperature (tempering) to reduce brittleness. Ideal for structural or load-bearing parts.
- Case Hardening – Hardens only the outer surface while retaining a ductile core. Techniques include carburizing or nitriding. Commonly used for gears, cams, and wear-resistant components.
Comparison Table: Heat Treatment Options
| Treatment | Purpose | Application |
|---|---|---|
| Annealing | Soften material, reduce stress | Tool steels, pre-machining |
| Normalizing | Improve uniformity and machinability | Carbon/alloy steels |
| Quenching & Tempering | Increase hardness and tensile strength | Structural parts, shafts |
| Case Hardening | Wear-resistant surface with tough core | Gears, pins, rollers |
Best Practices
- Specify treatment type and parameters in technical drawings.
- Control heating/cooling rates to avoid distortion or cracking.
- Verify results using Rockwell hardness tests or microstructure analysis.
At Onlyindustries, we incorporate both in-house and certified heat treatment processes tailored to your steel part’s mechanical and structural needs, ensuring performance and reliability in real-world applications.
Applications of CNC Machined Steel Parts
Steel’s unmatched strength, versatility, and thermal performance make it a go-to material for high-performance components across diverse industries. CNC machining transforms steel into parts with exceptional accuracy and reliability tailored to each application’s needs.
Aerospace Applications
In aerospace, where safety and strength are paramount, CNC-machined steel parts play critical roles. Components such as landing gear brackets, actuator mounts, and turbine casing supports are often made from alloy or stainless steels due to their strength-to-weight ratio and fatigue resistance. The tight tolerances achieved through CNC ensure reliable performance under dynamic loads and extreme environments.
Automotive Applications
Automotive manufacturers rely on steel machining for essential parts like gear shafts, transmission housings, engine brackets, and steering columns. Carbon steels like 1045 and alloy steels like 4140 are preferred for their balance between machinability and mechanical strength. These components must endure heat, vibration, and long-term wear, making precise CNC finishing vital for performance and longevity.
Oil & Gas Sector
Steel components in oil and gas—such as pump housings, flanges, couplings, and valve bodies—must resist high pressure, chemical exposure, and corrosion. Alloy and stainless steels (e.g., 316, 17-4PH) are commonly machined to deliver the structural strength and durability needed in harsh drilling environments. Onlyindustries applies specialized post-treatments to further enhance corrosion resistance in offshore or downhole use.
Medical and Surgical Devices
Stainless steel (especially 304 and 316) is a staple material for surgical instruments, MRI-compatible frames, and orthopedic devices. CNC machining allows for the production of precise, clean, and highly polished surfaces suitable for sterile and biocompatible applications. These components demand exacting tolerances and finishes, often achieved through multi-axis CNC and post-process polishing.
Defense and Tactical Equipment
Military-grade CNC steel parts include firearm receivers, armor plates, rugged housings, and mounting hardware. Tool steels and hardened alloys are preferred for their toughness and impact resistance. In mission-critical defense applications, dimensional accuracy and repeatability directly impact reliability and safety.
Industrial Machinery
In industrial settings, CNC-machined steel parts include gear wheels, fasteners, support structures, and rotating shafts. These components often require customization for load handling, vibration dampening, or integration with automation systems. CNC processes provide the flexibility to produce both standard and complex shapes efficiently and cost-effectively.

Summary Table: Industries and Steel Part Examples
| Industry | Common Steel Components |
|---|---|
| Aerospace | Landing gear, engine mounts, structural arms |
| Automotive | Gear shafts, suspension arms, motor brackets |
| Oil & Gas | Valve bodies, couplings, pressure flanges |
| Medical | Surgical tools, implant frames, MRI supports |
| Defense | Gun frames, armor enclosures, tactical mounts |
| Industrial | Bearings, fasteners, heavy-duty shafts |
At Onlyindustries, we serve all these sectors with precision-machined steel components built to meet rigorous standards in function, form, and longevity.
Advantages of CNC Machining Steel
Steel remains one of the most versatile and high-performing materials in manufacturing. When combined with CNC machining, it unlocks unmatched advantages in precision engineering, performance reliability, and application flexibility.
High Dimensional Accuracy
CNC machining provides consistent, tight-tolerance results that are crucial for steel parts used in demanding environments. With tolerances as fine as ±0.005 mm, it ensures reliable fits and functionality for complex assemblies. This level of accuracy is critical for aerospace actuators, automotive shafts, and precision defense components.

Structural Integrity for Load-Bearing Applications
Steel’s high yield and tensile strength make it ideal for structural parts under constant or variable loads. CNC machining preserves this integrity while allowing intricate designs that wouldn’t be feasible with casting or stamping. It’s commonly used for load-bearing engine mounts, suspension components, and pressure-retaining housings.
Repeatability for Mass Production
Once the CNC program is optimized, it delivers identical parts in every cycle—making it ideal for scaling from prototyping to low-volume production. This ensures manufacturing consistency in automotive, oil & gas, and medical sectors where variation could lead to functional failure or regulatory non-compliance.
Customizability for Complex Geometries
Multi-axis CNC machining enables the creation of complex steel geometries—undercuts, pockets, threads, and intricate contours—that are difficult or impossible with traditional machining. Whether you’re machining a multi-cavity mold plate or a compound-angle actuator bracket, CNC handles the complexity with precision.
Post-Processing Compatibility
Steel parts machined by CNC are ideal candidates for further enhancement via post-processing:
- Heat Treatments (quenching, tempering, case hardening)
- Coatings (black oxide, zinc/nickel plating)
- Finishing (grinding, polishing, deburring)
These steps improve mechanical performance, corrosion resistance, and surface aesthetics.
Sustainability and Material Reusability
Steel is 100% recyclable without loss of properties. CNC machining minimizes material waste through precision cutting and simulation-driven toolpaths. This makes it a preferred method for eco-conscious manufacturers who prioritize both quality and environmental responsibility.
Summary of Benefits
| Advantage | Description |
|---|---|
| Dimensional Accuracy | Maintains tight tolerances for precision fits |
| Mechanical Strength | Supports heavy loads and harsh conditions |
| Production Consistency | Delivers identical parts across production runs |
| Design Flexibility | Supports intricate and custom part geometries |
| Post-Process Ready | Compatible with heat treating and finishing methods |
| Sustainability | Minimizes waste; fully recyclable |
Whether you’re developing advanced robotics, engine components, or structural frames, CNC machining steel delivers the reliable performance needed in high-stakes engineering.
Challenges and How to Address Them
While CNC machining steel offers impressive strength and versatility, it also presents unique challenges that require strategic solutions. From tool wear to work hardening, understanding these issues helps maintain productivity and quality.
Tool Wear Due to Hardness
Steel’s density and toughness can accelerate tool wear—especially in alloy and tool steels. Excessive wear leads to dimensional inaccuracies and surface imperfections.

Solution:
- Use carbide or coated tools (e.g., TiAlN or TiCN) for durability.
- Optimize speeds and feeds to reduce unnecessary heat and friction.
- Implement toolpath simulations to avoid redundant cutting movements.
Work Hardening in Stainless Steels
Stainless steel tends to harden under heat and pressure during machining, which makes cutting progressively more difficult and shortens tool life.
Solution:
- Use sharp, positive-rake tools and rigid setups to minimize tool deflection.
- Maintain consistent feed rates and avoid dwelling.
- Apply high-pressure coolant to evacuate chips quickly and cool the work zone.
Excessive Heat Generation
Friction between the tool and steel surface generates high temperatures, which can damage the workpiece, degrade the tool, and affect tolerances.
Solution:
- Use flood or mist coolant systems—especially for stainless and tool steels.
- Incorporate air blast cooling when dry machining.
- Set conservative depth of cut and feed rate during finishing passes.
Burr Formation
Steel machining often produces burrs—sharp residual material that can compromise fit, safety, and aesthetics.
Solution:
- Apply deburring operations like manual edge breaking, abrasive blasting, or chamfer tools.
- Design features like fillets or chamfers to reduce burr-prone edges.
- Use finishing passes at lower feed rates with sharper tools.
Maintaining Tolerances During Heat Treatment
Post-machining treatments such as quenching or tempering can distort steel components, throwing off critical dimensions.
Solution:
- Use pre-hardened materials when tight tolerances are required.
- Rough machine before heat treatment and finish after.
- Apply stress-relief procedures between rough and finish passes.
Summary Table: Common CNC Steel Challenges
| Challenge | Solution |
|---|---|
| Tool Wear | Carbide tools, proper coatings, toolpath optimization |
| Work Hardening | Sharp tools, no dwell, continuous feed |
| Heat Buildup | Coolants, air blast, reduced speeds/feeds |
| Burr Formation | Edge design, deburring operations, finishing passes |
| Tolerance Loss Post-Treatment | Use pre-hardened material or stress-relief machining |
By proactively addressing these challenges, engineers and machinists can fully capitalize on the benefits of steel machining while minimizing cost, downtime, and defect risk.
Best Practices from the Shop Floor
To unlock efficient and accurate steel machining, incorporating shop-floor best practices is essential. These tips enhance quality, boost productivity, and extend machine and tool life.
Use Pre‑Hardened or Normalized Steels
Choose pre-hardened or normalized steel grades to minimize distortion during machining and heat treatment. This ensures consistent dimensional control throughout the process.

Avoid Sudden Feed‑Rate Changes
Rapid feed variations can induce chatter and tool deflection—impacting surface finish and part accuracy. Maintain consistent feed rates and apply gradual acceleration/deceleration in CAM programs.
Ensure Rigidity of Fixtures and Machine Setups
Vibration undermines precision and prematurely wears tools. Use robust fixturing, proper workholding, and test setups before roughing to improve repeatability.
Apply DFM Principles in Part Design
Design components with machining in mind:
- Chamfers and fillets: Reduce tool entry stress and burr formation.
- Uniform wall thickness: Avoid warping and vibration.
- Access planning: Ensure cutter paths are unobstructed.
Perform Regular Tool Wear Inspections
Monitor tool life by measuring chip size, surface finish, and tool edge condition. Replace or regrind tools proactively to maintain tolerances and part quality.
Calibrate and Maintain Machines Frequently
Check axes alignment, backlash, and spindle runout regularly. Routine calibration ensures dimensional consistency, especially for tight-tolerance parts.
Encourage Feedback and Continuous Improvement
Facilitate open communication across shifts. Share observations on tooling, programming, and materials to identify recurring issues and implement process improvements.
Track and Analyze Production Metrics
Use KPIs such as cycle time, scrap rate, and tool replacement frequency to identify bottlenecks. This data-driven approach enables iterative optimization of machining operations.
By integrating these shop-floor practices, manufacturers enhance CNC steel machining efficiency, uphold quality standards, and reduce costs—ultimately delivering exceptional parts on time.
Why Choose Onlyindustries for CNC Steel Machining?
If precision, speed, and reliability are non-negotiables in your steel component manufacturing, Onlyindustries is your ideal partner. Here’s why our CNC steel machining solutions consistently exceed industry expectations.
Deep Engineering Expertise
Every steel part we manufacture is backed by seasoned mechanical engineers who understand the nuances of carbon steel, alloy steel, stainless steel, and tool steels. From design-for-manufacturing (DFM) consultations to post-machining treatments, our technical team guides your project at every step to ensure form, fit, and function.
Precision Machining Capability
We operate high-end CNC machining centers capable of holding tolerances as tight as ±0.005 mm. Our machinery includes:
- Multi-axis vertical and horizontal machining centers
- Swiss lathes for miniature and complex geometries
- In-house EDM for intricate steel features
In‑Process & Final Quality Control
Our comprehensive quality protocol includes:
- First Article Inspection (FAI) for every production batch
- Coordinate Measuring Machine (CMM) reporting
- Surface roughness and hardness verification
- PPAP, RoHS, and ISO 9001:2015 compliance documentation
Prototyping to Production Scalability
Whether you need one-off validation parts or a full production run, we support all scales with the same consistency. Our flexible MOQ policy and tiered pricing allow cost-effective scaling from R&D to market launch.
Global Logistics and Packaging
From aerospace engine parts to automotive powertrain components, we ship globally using corrosion-resistant, impact-proof packaging tailored to your delivery route and customs requirements.
Responsive Communication & Support
You’ll never be left in the dark. Our bilingual project managers provide proactive updates, technical insights, and after-sale follow-ups to ensure your satisfaction at every touchpoint.
Choosing Onlyindustries means partnering with a CNC machining expert that delivers accuracy, reliability, and continuous improvement—no matter how demanding your steel parts may be.
Conclusion
CNC machining steel is the backbone of modern industrial manufacturing. Its unmatched combination of strength, versatility, and machinability makes it ideal for high-performance applications across aerospace, automotive, oil & gas, medical, and defense industries. From carbon and alloy steels to stainless and tool steels, each grade offers unique benefits when processed with the right tools, parameters, and post-treatments.
By understanding the machining challenges and applying best practices—such as precise tooling, effective heat treatment, and robust quality control—you can achieve exceptional outcomes that meet both engineering and commercial expectations. Whether it’s low-volume prototyping or high-volume production, steel remains a go-to material for demanding environments where reliability and precision matter most.
At Onlyindustries, we combine cutting-edge CNC equipment with engineering insight to deliver steel parts with tight tolerances, flawless finishes, and scalable production capabilities. If you’re looking to turn your CAD designs into high-strength, high-performance steel components, we’re here to help.
Need Custom Steel Parts?
If your project demands precision-engineered steel components, Onlyindustries is your go-to partner for CNC machining excellence. We specialize in producing complex, high-tolerance steel parts tailored to your exact specifications—whether you’re working on aerospace brackets, automotive transmission housings, oilfield components, or medical tooling.
Our team of engineers will support you from the earliest stages of DFM (Design for Manufacturability) through to final production, ensuring every detail—from material selection to surface finish—is aligned with your functional and performance goals. We offer competitive lead times, low to medium batch flexibility, and global shipping with transparent logistics.
Let us help you take your product from concept to reality—efficiently, accurately, and reliably. Reach out now to start your steel machining project with confidence.
Contact us today for a technical consultation or to request a fast, customized quote.