Materials Guide
Material choice sets your part's cost, weight, lifespan, and lead time before a single chip is cut. This is the guidance we give our own customers — including the parts where the cheaper metal is the better engineering call.
Start here unless you have a reason not to
Strong enough for most structural parts, a third the weight of steel, excellent thermal conductivity, and the fastest-cutting common metal — which is why it's also the cheapest to machine. Anodize it for wear resistance and color.
Typical use
Enclosures, brackets, fixtures, heat sinks, drone and robotics parts
Watch out
Not the right call above ~300°F sustained, or where hardness matters more than weight.
When 6061 isn't strong enough
Nearly double the tensile strength of 6061 — comparable to many steels — while staying light. The standard for aircraft structure and anything highly loaded that still has to fly, ride, or be carried.
Typical use
Aerospace structure, suspension components, high-stress brackets
Watch out
Costs more, welds poorly, and is more prone to corrosion than 6061 — anodize or coat it.
Corrosion resistance without drama
303 is the free-machining variant — pick it when the part is mostly machined features. 304 is tougher and more corrosion-resistant — pick it for welded assemblies or wet environments.
Typical use
Food equipment, marine hardware, fittings, shafts in wet service
Watch out
Work-hardens: tight-tolerance thin features cost more than they would in aluminum.
Stainless that acts like tool steel
Precipitation-hardening stainless that heat-treats to 44 HRC while keeping corrosion resistance. When a part needs to be hard, strong, and rust-proof at once, this is usually the answer.
Typical use
Valve internals, surgical instruments, high-load pins and shafts
Watch out
Specify the condition (H900, H1025…) on your drawing — properties differ a lot.
Cheap strength, honest work
1018 for weldable brackets and fixtures where cost wins. 4140 when you need real mechanical strength and the option to harden. Neither resists rust — plan on plating, painting, or oil.
Typical use
Fixtures, weldments, shafts, gears, tooling
Watch out
If the part lives outdoors or in a wet environment, budget for coating from day one.
The fastest metal through a machine
Free-machining brass cuts faster than anything else we run, which often makes brass parts cheaper than the same geometry in steel despite higher material cost. Naturally corrosion-resistant and non-sparking.
Typical use
Fittings, valve bodies, electrical contacts, decorative hardware
Watch out
Soft — don't spec it for structural loads or wear surfaces.
For when the part matters more than the price
The best strength-to-weight ratio of any common engineering metal, biocompatible, and corrosion-proof in nearly everything. Machining it is slow and hard on tools — that's most of what you're paying for.
Typical use
Aerospace, medical implants and instruments, motorsport
Watch out
Expect 5–10× the machining cost of aluminum. Prototype in 6061, cut over when the design settles.
Plastics that behave like parts, not toys
Delrin (acetal) holds tight tolerances and machines beautifully — the default plastic. UHMW for wear strips and impact. PEEK when you need plastic that survives heat, chemicals, and autoclaves.
Typical use
Bushings, wear parts, insulators, seals, food-contact components
Watch out
Plastics move with temperature and moisture — tolerance expectations should account for it.
Every quote gets human eyes from people who machine these materials daily. Note your loading, environment, and budget — we'll tell you what we'd make it from.
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