The material is usually the first decision in a part, and it drives almost everything after it: which process runs the job, how fast the spindle can turn, what the surface finish looks like, whether the part needs a coating, and what it costs.
Below are the materials we run routinely, with the specific grades. If your drawing names a grade we have not listed, send it anyway — we will tell you whether we can source it reliably rather than substitute something close and hope you do not notice.
Materials and Typical Grades
| Brass & copper | C3604 (free-cutting), H62, H59 — the most-machined family in the shop |
|---|---|
| Stainless steel | 303 (free-cutting), 304 (general corrosion resistance), 316 (chloride resistance, medical) |
| Aluminum | 6061-T6 (structural), 6063, 7075 (high strength) |
| Carbon steel | 20# (low carbon), 45# (medium carbon), 12L14 (free-cutting) |
| Engineering plastics | POM-C, PA6 nylon, PEEK, PTFE, ABS |
How to choose a material
Three questions usually decide it. What does the part have to resist? — corrosion, heat, wear, chemicals. What does it have to do mechanically? — carry load, slide, insulate, seal. And what does the assembly require? — magnetic or non-magnetic, conductive or not, plated or bare.
The fourth question is the one that surprises people: does the grade have to be machinable in volume? A material that machines beautifully in a prototype can be the wrong choice for a production run if it is abrasive, gummy, or prone to work-hardening. Where that trade-off exists, we will flag it at quotation stage.
Material and cost
Material is rarely the largest line in a quotation — machine time usually is — but the grade affects both. A free-cutting material such as C3604 brass or 12L14 steel machines two to three times faster than one that is gummy or prone to work-hardening, and that difference lands directly in the price per piece. Where two grades would both do the job, it is worth asking which one machines better before settling on a favourite.
The second cost driver is availability. Grades we stock and run daily come with short lead times; a specialist material can add weeks before the first chip is cut. If your project has a fixed deadline, say so with the enquiry — that often decides the question more than any property on a datasheet.