CNC Material Selector
Three ways in, depending on what you already know: find a material from what your part has to do, compare candidates side by side, or look up a grade you're already considering and see the honest trade-offs and alternatives. 50 grades we machine day to day — real data, no sign-up.
Leave 0 if strength isn't the driver.
Easier machining = lower cost and shorter lead time.
Leave 0 to ignore. Lower = lighter part.
Searches real applications and finishes.
Pick up to three grades to put side by side.
Then see its properties — and what to move to if it isn't quite right.
Send Your Drawing for a Same-Day Quote
Talk directly to the engineers who will machine your parts — no account managers, no trading-company markups. Complimentary DFM review with every enquiry.
How to choose a material for a machined part
Material choice drives more of a machined part's cost than most people expect. It sets the cycle time, the tool wear, the achievable tolerance and finish, and the raw stock price — which is why two parts with identical geometry can differ several-fold in price purely on the grade specified. The trap is optimising for one property in isolation: specifying a superalloy for a bracket that will never see 200°C, or a free-machining grade for a part that needs corrosion resistance.
In practice you are balancing four things: strength (tensile, and how it holds up at temperature), corrosion resistance, weight (density — critical if there is a mass budget), and machinability (which is really a proxy for cost and lead time). The selector above ranks results easiest-to-machine first for exactly that reason: where two grades both satisfy the engineering requirement, the easier one is nearly always the cheaper, quicker part.
Some rules of thumb worth knowing. Aluminium 6061-T6 and 6082-T6 are near-equivalent and excellent to machine — 6082 is the common UK grade, 6061 the US one. Stainless 303 is free-machining and ideal for turned fittings, but 316/316L is the grade for corrosion resistance, medical and food-contact work. Titanium Grade 5 gives the best all-round strength-to-weight but is genuinely difficult to cut. Nickel superalloys such as Inconel 718 and Waspaloy work-harden rapidly and generate extreme cutting temperatures — expect additional cost and lead time over standard alloys, and talk to us early.
Every figure in this tool comes from the materials we machine day to day, with full MTR and CoC documentation standard on every order. Standard tolerance is ±0.010 mm (ISO 2768-f) on most metals; engineering plastics are wider because of thermal dimensional instability. If you are torn between two grades, send us the part — a DFM review is free and we would rather tell you the cheaper option than machine the expensive one.
Choosing a CNC material — FAQ
Which material is easiest to CNC machine?
Brass CZ121 and CZ131 are the most economical to machine — their chip-breaking behaviour allows high speeds and excellent surface finish. Among aluminiums, 6061-T6 and 6082-T6 are excellent. Free-machining stainless 303 is the easiest of the stainless grades. Easier machining generally means lower cost and shorter lead time.
What is the difference between 6061 and 6082 aluminium?
They are near-equivalent general-engineering grades with the same typical tensile strength (around 310 MPa) and identical machinability. 6082-T6 is the common UK/European grade; 6061-T6 is the common US grade. For most parts they are interchangeable — we stock both.
What is the difference between 303, 304 and 316 stainless?
303 is free-machining, so it is the easiest to cut and best for turned fittings and shafts, but it has lower corrosion resistance. 304 is the general-purpose grade. 316/316L adds molybdenum for markedly better corrosion resistance, which is why it is the default for medical, marine and food-contact work. Both 304 and 316 work-harden during cutting.
Which material should I use for a medical implant component?
Titanium Grade 23 (Ti-6Al-4V ELI, BS EN ISO 5832-3 ELI) is the usual choice for implantable devices, electropolished to Ra ≤0.4 µm. 316L stainless is standard for surgical instruments. Both are grades we machine routinely.
What is the strongest material you machine?
By tensile strength: MP35N at 1,930 MPa and Inconel 718 at 1,375 MPa lead the metals, with 440C stainless reaching 1,970 MPa heat-treated. All are difficult to machine, which affects cost and lead time — the selector above ranks by machinability so you can see the trade-off.
Which metal has the best strength-to-weight ratio?
Titanium Grade 5 (Ti-6Al-4V) at 950 MPa and 4.43 g/cm³ is the usual answer for demanding work, with aluminium 7075-T6 (572 MPa at 2.81 g/cm³) lighter still where the loads allow. Use the compare mode above to weigh them against each other directly.