Is 6061-T6 good for CNC machining?

Yes — it is the most machined aluminum alloy in the world. It cuts fast, machines clean, welds and anodizes well, and costs less than most alternatives. It is the default choice for brackets, housings, fixtures and enclosures unless a specific requirement rules it out.

What is the difference between 6061-T6 and 7075-T6?

7075 is nearly twice as strong but costs more, machines somewhat slower and corrodes more easily; 6061 is cheaper, weldable and corrosion-resistant. Use 7075 for high-load structural parts and 6061 for everything else.

How much does 6061 CNC machining cost?

A simple 6061 bracket in the 100-piece range typically lands in the low single-digit dollars per piece from Chinese factories; complex 5-axis housings run higher. Material itself is cheap — design features like deep thin pockets drive the price far more than the alloy.

Can 6061 be anodized?

Yes, and it anodizes better than almost any other alloy — clear and black Type II and hardcoat Type III are all standard. Note that anodize adds roughly 0.002–0.008 mm per surface, so tight dimensions should be specified post-anodize.

Materials · Aluminum

Aluminum 6061 CNC Machining: The Default Alloy, Done Right

By the engineering team at ROK Precision, Bao'an, Shenzhen · Updated November 2026 · 6 min read

If you ask ten machine shops which alloy they machine most, all ten will say 6061-T6. It is the workhorse of machined aluminum: cheap, fast to cut, easy to finish, forgiving in service. That popularity has a downside — parts get drawn in 6061 by habit when a different alloy would be better, and get priced carelessly because "it's just aluminum." Here is how we approach 6061 on our floor, and how to get the most from it.

Why 6061 dominates machined parts

Machinability: high cutting speeds, predictable chip breaking, excellent surface finish without exotic tooling. Machining time — the biggest cost driver — is among the lowest of any structural alloy.
Availability: plate, bar and tube in every size, everywhere. No mill minimums, no 12-week lead times, no substitution games.
Corrosion resistance: fine for most indoor and general industrial environments; anodizing extends it further.
Weldability: unlike 7075, 6061 welds properly (4043 or 5356 filler), which matters for welded-machined hybrid assemblies.
Finishability: among the best anodizing response of any alloy — clear, black and colored Type II, plus hardcoat Type III, all come out even and bright.

6061 tempers: T6, T651 and what the numbers mean

T6 is solution-treated and artificially aged — the standard temper, ~276 MPa tensile. T651 is T6 with stress relief by stretching; it's what you want for large plates that will be heavily machined, because internal stress otherwise warps parts as material is removed. When a customer complains that "machining moved my flatness," the missing word is almost always 651. For plates thicker than ~25 mm with flatness requirements, we default to 6061-T651 and flag it on the quote.

CNC milling an aluminum 6061 enclosure part — 3-axis milling of a 6061-T6 enclosure — pocketing is where 6061 design choices show up on the invoice.

What drives the price of a 6061 part

The alloy is rarely the reason a 6061 quote is high. In rough order of impact:

Deep, narrow pockets. A pocket deeper than 4× its width forces long tools, light cuts and slow feeds. Widening a pocket or adding a corner relief often cuts machining time 30–40%.
Tiny internal radii. Every corner radius smaller than the pocket depth demands slower cutting. A 3 mm radius instead of 1 mm is often free money.
Thin walls below 1 mm. They chatter, deflect and need finishing passes on both sides. 1.5–2 mm walls machine almost as rigid walls.
Tolerances on non-critical faces — the classic over-spec we covered in our tolerances guide.
Finish choice. As-machined is cheapest; bead blast + clear anodize adds a little; Type III hardcoat and masking schemes add more.

Where 6061 is the wrong answer

Requirement	Better choice	Why
High structural load, aerospace-grade strength	7075-T6	~1.7× the strength of 6061
Marine or continuous salt exposure	5052 sheet, or 6061 + hardcoat	6061 is good, not great, in chloride environments
Sliding against another surface (wear)	6061 + hard anodize, or a bronze insert	Bare 6061 galls under friction
Very tight flatness on large plates	Cast aluminum tooling plate (MIC-6 type)	Stress-free by manufacture, machines flat

Our 6061 capability snapshot

Parameter	Capability
Standard tolerance	±0.1 mm
Critical-feature tolerance	±0.005 mm, 100% CMM verified
Stock forms	Plate to 200 mm, bar Ø3–300 mm, tube, extrusion profiles
Finishes	As-machined, bead blast, Type II/III anodize (clear/black/colored), chromate, powder coat
Batch range	1 prototype to 50,000+ production

Frequently asked questions

Should I specify T6 or T651?

T6 for bars and small plates; T651 whenever the part comes from a plate thicker than ~25 mm or has flatness/parallelism callouts. It costs marginally more and prevents the classic post-machining warp.

Does anodizing change my tolerances?

Yes — hardcoat Type III builds 0.02–0.05 mm per surface; Type II adds roughly 0.002–0.008 mm. Specify tight dimensions as post-anodize and note which surfaces are masked; we plan the sequence accordingly.

Is 6061 cheaper than 7075?

Material cost is roughly half, machining is faster, and quotes reflect both. If 6061's strength meets the load case, specifying 7075 "to be safe" is a real cost with no function.