C360 Free-Cutting Brass vs C260 Cartridge Brass
C360 and C260 are both brasses but optimized for opposite processes. C360 free-cutting brass contains lead for the highest machinability of any common copper alloy, making it the standard for turned fittings and valves. C260 cartridge brass is leaded-free and far more ductile, formulated for deep drawing and cold forming. The choice comes down to high-speed machining versus formability.
The verdict
Choose C360 for high-speed machined parts — fittings, valves, and screw-machine components where cutting speed and finish dominate. Choose C260 when the part is deep-drawn, stamped, or cold-formed, since its higher ductility makes it the standard cartridge and forming brass.
Side-by-side data
| Property | C360 Free-Cutting Brass | C260 Cartridge Brass |
|---|---|---|
| Category | Copper Alloy | Copper Alloy |
| Density (g/cm³) | 8.5 | 8.53 |
| Tensile strength (MPa) | 340 | 370 |
| Yield strength (MPa) | 125 | 150 |
| Elongation (%) | 53 | 45 |
| Hardness | 78 HB | 65 HB |
| Max service temp (°C) | 200 | 200 |
| Machinability | ●●●●● | ●●●●● |
| Corrosion resistance | ●●●●● | ●●●●● |
| Relative cost | ●●●●● | ●●●●● |
| Thermal cond. (W/m·K) | 115 | 120 |
| Typically used for | High-speed machined fittings & valves | Deep-drawn & formed brass parts |
Which should you choose?
Choose C360 Free-Cutting Brass when…
- Parts are machined on lathes or screw machines at high speed
- Maximum machinability (rated 5.0, the benchmark for brass) is the priority
- Fittings, valves, fasteners, and connectors are being turned
- Excellent chip breaking and surface finish reduce cycle time
- The part is machined rather than deep-formed or drawn
- Good corrosion resistance (rating 4.0) suits plumbing and fluid parts
Choose C260 Cartridge Brass when…
- The part is deep-drawn, stamped, or heavily cold-formed
- Higher ductility for forming is essential (the classic cartridge brass)
- Lead-free composition is required for the application
- The process is sheet-metal forming rather than high-speed machining
- Slightly higher tensile (~370 MPa) and yield (~150 MPa) are useful
- Ammunition cases, terminals, and formed hardware are involved
Key differences that matter
- C360 is leaded free-cutting brass; C260 cartridge brass is lead-free and built for forming
- Machinability is the key gap: C360 at 5.0 (the brass benchmark) versus C260 at 3.5
- C260 is more ductile for deep drawing (elongation ~45%), the reason it is the classic cartridge brass
- C360's lead acts as a chip breaker and lubricant, enabling the fastest cutting of any common copper alloy
- C260 shows slightly higher tensile and yield (370/150 vs 340/125 MPa), reflecting its forming-oriented temper
- Both have the same corrosion rating (4.0) and similar thermal conductivity (~115-120 W/m-K)
- C360's lead can disqualify it from lead-restricted drinking-water and food applications; C260 is lead-free
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Why is C360 so much easier to machine?
C360 contains lead, which forms tiny dispersed particles that break chips and lubricate the cut. This lets tools run at high speed with excellent finish and long tool life, earning it the maximum brass machinability rating of 5.0. C260 lacks that lead, so it is gummier and rated lower at 3.5.
Which brass is better for deep drawing?
C260 cartridge brass is far better for deep drawing. Its high ductility, around 45% elongation, lets it be drawn into deep, complex shapes without cracking, which is why it is the traditional alloy for ammunition cases and formed hardware. C360's lead makes it brittle in forming and unsuitable for deep draws.
Does the lead in C360 limit its use?
Yes. The lead that makes C360 so machinable can disqualify it from drinking-water, food-contact, and other lead-restricted applications under regulations like the U.S. Safe Drinking Water Act. For those uses, a low-lead or lead-free brass such as C260 or a dedicated potable-water alloy is required instead.
Are their corrosion and conductivity similar?
Yes. Both share a corrosion rating of 4.0 and similar thermal conductivity near 115 to 120 W/m-K, so for plumbing, fittings, and electrical-mechanical parts they perform comparably in service. The practical choice between them is driven by the manufacturing process: high-speed machining favors C360, deep forming favors C260.
Property values are typical/nominal figures for early-stage guidance only and vary by temper, grade, supplier and heat treatment. Confirm critical specifications against a certified datasheet or with an mfgiq engineer before production.