What is the Cheapest Metal to CNC? A Guide for Cost-Saving Machining Projects

For businesses, product developers, and hobbyists launching CNC machining projects, cost control is just as critical as precision and performance. Choosing the right metal can slash production expenses without sacrificing quality—especially for high-volume orders or tight-budget projects. If you’re asking, “What is the cheapest metal to CNC?”, you need more than a low-price answer: you need a material that balances affordability, machinability, and fit for your specific use case.

In this guide, we’ll break down the top 3 cheapest metals for CNC machining, explain why they’re cost-effective, their key machining traits, ideal applications, and hidden costs to avoid. By the end, you’ll know exactly how to pick a low-cost metal that meets your project’s needs—and how to maximize value from start to finish.

Low-carbon steel (also called mild steel) is widely regarded as the cheapest metal for CNC machining—and for good reason. Made of iron with just 0.05–0.25% carbon content, it’s one of the most abundant and mass-produced metals globally, keeping raw material costs low.

▶  Why Low-Carbon Steel Is Cost-Effective for CNC

     ●  Ultra-high availability: Low-carbon steel is manufactured in massive quantities for construction, automotive, and industrial industries. This high supply keeps raw material prices stable and affordable year-round.

     ●  Excellent machinability: Its low carbon content makes it soft and ductile, so CNC tools cut through it with minimal resistance. This reduces tool wear (lowering tool replacement costs) and shortens machining time (cutting labor expenses).

     ●  No pre-processing needed: Unlike high-carbon steel, low-carbon steel doesn’t require pre-heat treatment before CNC machining. This skips extra steps and saves money on setup.

▶  Key CNC Machining Characteristics of Low-Carbon Steel

     ●  Cutting speed: Moderate to high—works seamlessly with CNC lathes and milling machines.

     ●  Chip formation: Produces continuous, easy-to-clear chips, which reduces machine downtime from clogs.

     ●  Surface finish: Achieves smooth results with standard CNC tools; no special coatings are needed for basic structural parts.

▶  Ideal Uses for Low-Carbon Steel in CNC Projects

Low-carbon steel is perfect for parts where cost matters more than high strength or corrosion resistance, such as:

     ●  Structural components (brackets, frames, supports for machinery or furniture)

     ●  Fasteners (bolts, nuts, washers, and screws)

     ●  Automotive parts (engine mounts, chassis brackets, and undercarriage components)

     ●  Industrial hardware (handles, hinges, spacers, and tool bases)

The most popular low-carbon steel grades for CNC are 1018 (easy to machine and weld) and 1020 (slightly stronger, ideal for parts needing minor durability). Most CNC shops can achieve tolerances as tight as ±0.005mm with these grades—even for high-volume orders.

If your project needs lightweight parts (without losing machinability), aluminum alloy is the next best low-cost option. It’s often only slightly more expensive than low-carbon steel—but its unique benefits (like corrosion resistance and faster machining) can justify the small price difference.

▶  Why Aluminum Alloy Is Cost-Effective for CNC

     ●  Low density = lower shipping costs: Aluminum weighs 1/3 of steel. For international orders or large parts, this cuts shipping expenses drastically—a major win for businesses importing CNC components.

     ●  Faster machining = lower labor costs: Aluminum is softer than steel, so CNC machines can cut it up to 2x faster. Shorter cycle times mean you pay less for labor per part, even for high-volume runs.

     ●  No post-processing for corrosion resistance: Unlike steel, aluminum forms a natural oxide layer that prevents rust. This eliminates costs for painting, galvanizing, or coating for most indoor/outdoor applications.

▶  Key CNC Machining Characteristics of Aluminum Alloy

     ●  Cutting speed: Very high—ideal for high-volume production (e.g., consumer electronics parts).

     ●  Chip formation: Produces small, broken chips that don’t clog CNC machines, reducing maintenance time and downtime.

     ●  Surface finish: Achieves a polished, professional look with minimal effort—perfect for parts needing aesthetic appeal (like laptop frames or phone cases).

▶  Ideal Uses for Aluminum Alloy in CNC Projects

Aluminum alloys like 6061 (versatile, with good strength) and 6063 (excellent for extruded parts) are widely used in:

     ●  Aerospace and automotive components (lightweight brackets, heat sinks, and interior parts)

     ●  Consumer electronics (phone cases, laptop frames, tablet stands, and speaker enclosures)

     ●  Industrial tools (lightweight handles, tool enclosures, and workbench accessories)

     ●  Drone and robotics parts (frames, propeller mounts, and sensor brackets)

For projects prioritizing weight savings (e.g., drone manufacturers or electric vehicle suppliers), aluminum often hits a “cost-performance sweet spot” that low-carbon steel can’t match.

Brass is slightly more expensive than low-carbon steel and aluminum—but it’s still a cost-effective choice for specific CNC projects, especially when you need electrical conductivity, corrosion resistance, or ultra-precise small parts.

▶  Why Brass Is Cost-Effective for CNC

     ●  Exceptional machinability: Brass is softer than steel and has low friction, so CNC tools glide through it smoothly. This reduces tool wear (extending tool life by 30–50% compared to steel) and allows for ultra-tight tolerances.

     ●  No coatings for conductivity: Brass is naturally conductive, so it’s perfect for electrical parts without needing expensive copper plating or treatments.

     ●  Low maintenance: Brass resists rust and tarnish in most environments (even humid or damp conditions), so you skip post-processing costs for corrosion protection.

▶  Key CNC Machining Characteristics of Brass

     ●  Cutting speed: High (similar to aluminum, but with better chip control for small parts).

     ●  Surface finish: Achieves a mirror-like polish with minimal effort—ideal for decorative parts or high-precision components.

     ●  Tolerance capability: Perfect for micro-CNC projects (e.g., small gears, electrical connectors) with tolerances as tight as ±0.002mm.

▶  Ideal Uses for Brass in CNC Projects

Brass is the go-to low-cost metal for:

     ●  Electrical components (connectors, terminals, switches, and circuit board parts)

     ●  Precision hardware (small gears, valves, fittings, and watch components)

     ●  Decorative parts (nameplates, decorative trim for furniture, and jewelry findings)

     ●  Plumbing parts (faucet handles, pipe fittings, and valve cores)

While brass has a higher upfront cost, its ability to skip post-processing (like plating) and longer tool life often makes it cheaper than steel for these niche applications.

Choosing the cheapest metal isn’t just about raw material price—hidden costs can quickly wipe out savings if you’re not careful. Here’s what to watch for:

     ●  Tool wear from low-quality metals: Some “cheap” metals (e.g., unalloyed steel with high impurities) dull CNC tools faster. Stick to standard grades (1018 steel, 6061 aluminum, C36000 brass) to minimize tool replacement costs.

     ●  Post-processing for corrosion resistance: Low-carbon steel needs painting, galvanizing, or powder coating if it will be exposed to moisture (e.g., outdoor parts). Factor these costs into your budget upfront.

     ●  Material waste from poor design: A poorly optimized part design can lead to more scrap metal (and higher costs). Work with a CNC provider that offers DFM (Design for Manufacturability) checks to reduce waste and lower per-part costs.

Follow these 3 simple steps to pick the right low-cost metal:

1. Define the part’s purpose:

        Structural parts (e.g., brackets): Low-carbon steel (cheapest).

        Lightweight parts (e.g., drone frames): Aluminum (better value than steel for weight savings).

        Electrical/precision parts (e.g., connectors): Brass (cheapest for conductivity/tight tolerances).

2. Calculate total costs (not just raw material price):

        Low-carbon steel is cheapest upfront, but aluminum may save you money on shipping and post-processing. Brass may cost more initially, but it eliminates plating costs for electrical parts.

3. Consider environmental conditions:

        Outdoor/wet environments: Aluminum or brass (resist rust).

        Indoor/dry environments: Low-carbon steel (no need for corrosion protection).

There’s no one-size-fits-all “cheapest metal to CNC”—the best choice depends on your part’s purpose, budget, and environment:

     ●  Cheapest for general structural parts: Low-carbon steel (1018).

     ●  Cheapest for lightweight/corrosion-resistant parts: Aluminum (6061).

     ●  Cheapest for electrical/precision parts: Brass (C36000).

The real key to saving money? Partner with a CNC machining provider that understands both materials and your unique needs. A good provider will help you:

     ●  Choose the cheapest metal that meets your performance requirements.

     ●  Optimize your design to reduce waste and machining time.

     ●  Get transparent pricing (no hidden fees for raw materials, machining, or post-processing).

If you’re ready to start your CNC project, send over your design (CAD files preferred) or describe your requirements. We’ll respond within 24 hours with a free, customized quote—and help you pick the cheapest metal that gets the job done right.

Q: Is low-carbon steel easier to CNC than aluminum?

A: No—aluminum is softer, so it’s faster to CNC than low-carbon steel. Low-carbon steel is easier to weld, but aluminum has better machinability for high-volume runs.

Q: Can brass be used for outdoor CNC parts?

A: Yes—brass resists tarnish and corrosion in most outdoor environments, though it may develop a patina over time (which is often desired for decorative parts).

Q: How much does CNC machining cost for low-carbon steel vs. aluminum?

A: On average, low-carbon steel machining costs 10–15% less than aluminum for simple parts. But for large parts, aluminum’s lower shipping costs can make it cheaper overall.