- Free-machining grades — 360 brass, 303 stainless, 12L14 steel — cut fast and hold finish
- 6061/7075 aluminum, 316 stainless, copper and titanium where the job demands them
- Machinability drives price: a free-cutting grade is cheaper to machine than an exotic one
- Mill certificates ship with every order
Machinability is the shop's first question
Two materials can look identical on a spec sheet and machine completely differently. Free-cutting brass (C360) runs circles around a gummy alloy; 12L14 steel parts from the bar while a high-alloy tool steel fights every pass. A machining shop chooses material partly for the finished part, and partly for how many parts it can make per hour, which is your price.
The grades that machine well, and when to pay for more
| Material | Machinability | When it is worth it |
|---|---|---|
| C360 brass | Excellent | Fittings, connectors, thermal |
| 303 stainless | Good | Shafts, fasteners, corrosion |
| 316 stainless | Fair | Salt, chemicals, marine |
| 6061 aluminum | Excellent | General structural |
| 12L14 / alloy steel | Good | Strength, wear |
| Titanium | Poor | Weight-critical, corrosion |
The pattern: the easier the material is to cut, the less you pay in cycle time and tooling. Pick the cheap, easy grade wherever the function allows, and reserve the expensive grades for the features that earn them.
Why machinability hits your price
A free-machining grade can run at double the feed of a gummy one, with a better finish and less tool wear. That is not a materials footnote — it is the single biggest lever on the machining line of your quote. A shop that asks 'why this alloy?' before quoting is saving you money.
Prove the grade
Material certificates ship with every order. If a supplier cannot show the mill cert, you cannot be sure the free-cutting grade you paid for is what reached the spindle.
Should I always use a free-machining grade?
No — machinability is one axis. Corrosion, strength and conductivity can force a harder-to-cut grade. The point is to use the easy grade wherever the function allows.
Do you machine plastics?
Yes — PEEK, Delrin, nylon and acetal, with the slower speeds and sharp tooling they need.
Name the job and we will name the grade that machines fast and still meets it.
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Standards referenced on this page
- ASTM A276/A276M-17 — Standard Specification for Stainless Steel Bars and Shapes
- ASTM B211/B211M-19 — Standard Specification for Aluminum-Alloy Rolled or Cold Finished Bar, Rod, and Wire
- ISO 9001 — Quality management systems — Requirements