If you've been specifying brass for machined parts, you've probably noticed more RFQs calling for "lead-free" or "low-lead" brass. Regulations like the Safe Drinking Water Act have tightened the rules on lead content in certain applications, and that's driving a real shift in material selection for manufacturers across plumbing, potable water, food processing, and consumer products.
Lead-free brass isn't a universal upgrade over traditional leaded brass like C360. It exists for specific, well-defined regulatory reasons. And it comes with real tradeoffs in machinability, cost, and process complexity that buyers and engineers should understand before specifying it.
This article breaks down the two most common lead-free and low-lead brass alloys used in precision machining — C27450 and C370 — and gives you a practical, honest comparison to help you make the right material decision for your application.
The driving force behind lead-free brass adoption is the Reduction of Lead in Drinking Water Act (RLDWA), which amended the Safe Drinking Water Act in 2011 and took effect on January 4, 2014. The law redefined "lead-free" from a maximum of 8% lead content down to a weighted average of no more than 0.25% lead across the wetted surfaces of pipes, pipe fittings, plumbing fittings, and fixtures.
That's a massive reduction, from 8% to 0.25%.
The law applies specifically to products intended for use in potable water systems. That includes plumbing components, valves, fittings, and any part that comes into contact with drinking water. Products must also meet certification standards like NSF/ANSI 61 (which tests what actually leaches into the water) and NSF/ANSI 372 (which verifies the lead content of the material itself).
Key exemptions: The lead-free requirement does not apply to components used exclusively for non-potable services — including manufacturing, industrial processing, irrigation, and outdoor watering. Fire hydrants are also exempt under the Community Fire Safety Act of 2013.
This matters because it means the regulations are targeted, not universal. Not every brass part needs to be lead-free. But for the applications that do fall under these rules, compliance isn't optional.
Lead has been added to brass alloys for decades — not carelessly, but deliberately, because it makes brass significantly easier to machine. At 2-3% by weight in alloys like C360, lead acts as a chip breaker and internal lubricant during cutting. It's the reason C360 is rated at 100 on the machinability index and why it's considered the benchmark for free-machining metals.
But "lead" as a word carries a lot of weight in public perception, largely because of legitimate concerns around lead paint and lead pipes. So it's worth being specific about what the actual risks are when it comes to lead in machined brass parts.
The risk with leaded brass is lead leaching — when brass is in sustained contact with water (especially soft, acidic, or hot water), trace amounts of lead can dissolve out of the alloy and into the water over time. This is a real and well-documented public health issue for potable water systems. There is no safe level of lead exposure in drinking water, and even small amounts can cause serious health effects, particularly for children.
That's why the regulations exist. Any brass component that contacts drinking water should be lead-free, full stop. The science and the law are clear on this.
For the vast majority of industrial machined parts, leaded brass like C360 is perfectly safe and remains the industry standard. There's no lead exposure pathway if you're making:
The lead is bound within the alloy matrix at a few percent by weight. It doesn't off-gas, it doesn't transfer through skin contact with a finished part, and it doesn't create dust in normal use. A machined brass fitting inside a pressure gauge or an electrical enclosure presents zero lead exposure risk to end users.
Lead paint was dangerous because of direct exposure pathways — children eating paint chips, and toxic dust generated during renovation work. A machined brass connector bolted inside an industrial assembly doesn't create those pathways. The concern about lead in brass is narrow and specific: prolonged contact with water intended for human consumption. Outside of that context, specifying lead-free brass over C360 adds cost and machining complexity without any safety benefit.
Bottom line: If your application involves potable water contact, lead-free brass is required and the right choice. For everything else, C360 remains the most efficient, cost-effective, and perfectly safe option.
C27450 is a true lead-free brass alloy with a maximum lead content of 0.25%, designed specifically to meet NSF/ANSI 61 and Safe Drinking Water Act requirements for potable water contact applications.
C27450 is the go-to alloy when full lead-free compliance is non-negotiable. It meets NSF/ANSI 61, NSF/ANSI 372, and the SDWA's 0.25% weighted average requirement. It also offers good forgeability and thread-rolling capability, and its scrap can be recycled alongside C360 and other standard brass alloys — a practical advantage for shops running mixed production.
C370, also designated C37000 and sometimes called "free-cutting Muntz metal," is a low-lead brass alloy that reduces lead content significantly compared to C360 while maintaining machinability closer to traditional leaded grades.
C370 occupies a middle ground. It contains roughly 1% lead — significantly less than C360's 3%, but above the 0.25% threshold for NSF/ANSI 61 "lead-free" certification. That means C370 meets reduced-lead requirements for some applications but does not qualify as lead-free under the Safe Drinking Water Act for potable water contact.
Where C370 shines is in applications where a manufacturer or end customer wants to reduce lead content for environmental or corporate responsibility reasons without needing full SDWA compliance. It also maintains forging performance close to conventional free-cutting alloys, which is important for hot-formed components.
Choose C27450 when:
Choose C370 when:
Stick with C360 when:
Lead-free and low-lead brass alloys exist for important reasons, but they're not a free upgrade. Buyers and engineers should go in with clear expectations about the tradeoffs.
C360 is rated at 100 on the machinability index. It's literally the reference standard. That rating exists because of its lead content: lead acts as a microscopic chip breaker, reducing friction at the cutting edge and promoting clean, short chips that clear easily.
Remove or reduce the lead, and the chip characteristics change. Lead-free alloys like C27450 produce longer, stringier chips that are harder to manage. Tool engagement generates more heat. Cutting forces increase. The result is a machinability rating around 70 for both C27450 and C370 — a 30% reduction from C360.
That's not a minor difference. It's the difference between a process that runs itself and one that requires more attention.
Slower speeds, shorter tool life, and more demanding chip management all translate to higher per-part costs. The exact premium depends on part complexity and volume, but for equivalent geometries, expect lead-free brass parts to cost more to machine than C360 parts.
C360 is forgiving. Shops can run it fast, hold tight tolerances, and get excellent surface finishes almost by default. Lead-free brass requires more intentional process management — adjusted feeds and speeds, different tooling geometries (sharper rake angles, different coatings), optimized coolant delivery, and closer attention to chip evacuation.
A shop that machines C360 all day can't simply swap in C27450 and expect the same results without process adjustments.
Lead-free alloys carry a price premium over C360. Availability can also be more limited depending on the form factor and quantity you need.
C360's lead content helps produce exceptionally smooth finishes directly off the machine. With lead-free alloys, achieving the same finish quality may require additional operations or more careful parameter optimization. For parts where surface finish is critical, this is worth factoring into your planning.
These tradeoffs are the cost of compliance — and when compliance is required, they're worth paying. The point is that specifying lead-free brass when it isn't required adds cost, complexity, and machining difficulty with no offsetting benefit. Choose it when you need it. Choose C360 when you don't.
If you've decided lead-free brass is the right choice for your application, here's what matters from a machining perspective.
Lead-free brass benefits from sharper cutting tools with higher positive rake angles. Uncoated carbide or PCD (polycrystalline diamond) tooling typically outperforms standard coated inserts. The goal is reducing cutting forces and heat generation at the tool edge.
Lead-free alloys generally require slower cutting speeds than C360 to manage heat and chip formation. Feed rates may need adjustment depending on the operation — lighter cuts can help maintain surface quality, while deeper cuts can sometimes improve chip breaking.
This is the biggest operational difference. Without lead acting as a chip breaker, lead-free brass produces long, continuous chips that can wrap around tooling, clog chip conveyors, and cause surface finish issues. Chip breaker geometry on inserts, peck drilling cycles, and effective coolant delivery all become more important.
Flood coolant is generally recommended for lead-free brass machining to manage heat and assist with chip evacuation. Some shops have success with high-pressure coolant directed at the cutting zone.
Lead-free brass can be more sensitive to dimensional variation from heat buildup during extended cutting cycles. In-process measurement and SPC become more important for high-tolerance work.
The practical reality is that machining lead-free brass well requires experience with these specific alloys. A shop that treats C27450 like C360 will produce inferior results. At Spex, we machine lead-free brass alloys regularly and have optimized our processes — tooling, speeds, feeds, and quality systems — specifically for these materials. The result is consistent dimensional accuracy and surface finish, even on complex geometries.
Lead-free brass machined components serve a growing range of applications driven by regulatory compliance and environmental responsibility:
Potable water systems — Valves, fittings, connectors, and distribution components that contact drinking water. This is the primary driver of lead-free brass demand, directly mandated by the Safe Drinking Water Act.
Food and beverage equipment — Processing components, fittings, and fluid handling parts where product contact surfaces must be free of lead contamination.
Medical devices — Certain fluid-path components in medical equipment where biocompatibility and contaminant-free materials are specified.
Consumer products — Hardware, fittings, and components in consumer-facing products where manufacturers have adopted lead-free policies for brand safety or market requirements.
HVAC and plumbing — Components in heating and cooling systems connected to potable water circuits, including mixing valves, manifolds, and distribution fittings.
Green building and LEED projects — Construction projects pursuing environmental certifications often specify lead-free materials throughout potable water systems as part of their sustainability requirements.
At Spex, we machine both traditional leaded brass (C360, C353) and lead-free alloys (C27450, C370) across our full range of capabilities — CNC milling, CNC turning, multi-spindle screw machining, and Swiss machining.
We've invested in optimizing our processes specifically for lead-free brass, including adjusted tooling, feeds and speeds, and chip management strategies that deliver the same tight tolerances and surface finish quality our customers expect from any material we run.
Whether you need 500 lead-free valve bodies or 500,000 NSF-compliant fittings, we have the experience and production capacity to deliver. Our ISO 9001:2015 certified quality system ensures full documentation — including material certifications, dimensional reports, and First Article Inspection Reports — for every order.
Need lead-free brass machined parts? Request a quote or learn more about our brass machining capabilities.
Yes — with the right process parameters and tooling. Lead-free alloys like C27450 are capable of holding tolerances down to ±0.002", comparable to what you'd achieve with C360. The difference is that lead-free brass requires more careful process management to maintain those tolerances consistently, particularly on long production runs where heat buildup can affect dimensional stability. An experienced shop with optimized processes for lead-free materials will deliver comparable precision.
The total cost increase comes from two sources: higher raw material prices for lead-free alloys and increased machining costs due to slower speeds, faster tool wear, and more demanding process control. The exact premium varies based on part complexity, volume, and the specific alloy, but for equivalent parts, lead-free brass typically costs more to produce than C360. For applications where lead-free isn't required by regulation, C360 remains the most cost-effective choice.
The key question is whether your part will contact potable water intended for human consumption. If yes, the Safe Drinking Water Act requires materials with no more than a weighted average of 0.25% lead on wetted surfaces. Components used exclusively for non-potable services — industrial processing, gas handling, irrigation, electrical applications — are exempt. If you're unsure, check your customer's specification or the applicable building codes for your end-use application. We're happy to help you determine the right alloy for your requirements.
No. C370 contains approximately 1% lead, which is well below C360's 3% but above the 0.25% maximum required by the SDWA for "lead-free" designation. C370 is more accurately described as "low-lead" or "reduced-lead" brass. If your application requires full SDWA or NSF/ANSI 61 compliance for potable water contact, C27450 (at ≤0.25% lead) is the appropriate choice.
Yes. We regularly run both traditional leaded brass (C360, C353) and lead-free alloys (C27450, C370) across our CNC turning, milling, multi-spindle, and Swiss machining equipment. Material segregation and traceability are managed through our ISO 9001:2015 quality system, ensuring no cross-contamination between alloy types. Each order includes full material certification and documentation.
Spex Precision Machine Technologies is a precision machining company based in Rochester, NY, specializing in custom brass, steel, stainless steel, and copper alloy components. Contact us to discuss your next project.
