Aluminum CNC machining, and every material we stock.
Most machined parts are aluminum, and most of those should be 6061-T6. Here’s how to choose between 6061 and 7075, when another material is the better call, and how each one machines.
- Grades
- 13, all stocked
- Priced in minutes
- 11
- Flagged tier
- Ti 6Al-4V · PEEK
- Stock ladder
- 0.25 – 4.5 in thick
- Your own stock
- Accepted with cert
6061 vs 7075: two aluminums cover almost everything.
Use 6061 unless the part is highly loaded. Use 7075 when it is and weight still matters. Both are stocked across the ladder, both price in minutes, and both anodize.
Aluminum 6061-T6
Price in minutesT6 · Start here
Strong enough for most structural parts, about a third the density of steel, with excellent thermal conductivity. It cuts fast, which keeps it inexpensive to machine, and anodizes cleanly in clear or black.
- Typical use
- Enclosures, brackets, plates, manifolds, heat sinks, robotics and drone structure
- Watch out
- Not the call above roughly 300 °F sustained, or where surface hardness matters more than weight.
Aluminum 7075-T651
Price in minutesT651 · When 6061 isn’t strong enough
Roughly double the tensile strength of 6061 — into the range of many steels — while staying light. The default for aircraft structure and highly loaded parts that still have to fly, ride or be carried.
- Typical use
- Aerospace structure, suspension and linkage parts, high-stress brackets
- Watch out
- Costs more, welds poorly and corrodes more readily than 6061. Anodize or coat it, and keep thin sections conservative.
Design tips for aluminum parts
Keep walls at 0.030 in or thicker, and internal corner radii at 0.031 in or larger so a 1/16 in end mill can reach. Thin ribs and sharp internal corners are the two features most likely to send a part to engineering review.
Stainless, steel, brass, titanium and plastics.
Eleven more grades, all stocked. Titanium and PEEK sit in a flagged pricing tier: an engineer sizes the stock and confirms the price.
Stainless 303
Price in minutesAnnealed · The free-machining stainless
Sulfur additions make 303 far easier to cut than the rest of the 300 series. Pick it for heavily machined parts that will never see a weld.
- Typical use
- Fittings, shafts, fasteners, instrument bodies
- Watch out
- Don’t weld it. Slightly less corrosion resistant than 304, and it work-hardens.
Stainless 304
Price in minutesAnnealed · The one you weld
Tougher and more corrosion resistant than 303, and it welds cleanly. The usual choice for wet service and food-safety or marine specs.
- Typical use
- Food and beverage equipment, marine hardware, weldments
- Watch out
- Cuts slower than 303. Tight tolerances on thin features cost more here than in aluminum.
Stainless 17-4 PH
Price in minutesCond A · H900 · Stainless that behaves like tool steel
Heat-treats to roughly 44 HRC in H900 while keeping its corrosion resistance — for parts that must be hard, strong and rust-proof at once.
- Typical use
- Valve internals, instrument components, high-load pins and shafts
- Watch out
- Call out the condition on your print. Condition A and H900 machine and measure differently.
Steel 1018
Price in minutesCold rolled · Cheap, predictable strength
Weldable, predictable and inexpensive. Right for fixtures and structural parts where cost wins and a coating handles corrosion.
- Typical use
- Fixtures, weldment components, spacers, tooling plates
- Watch out
- No corrosion resistance. Budget for plating, black oxide, paint or oil from day one.
Steel 4140
Price in minutesAnnealed · pre-hard · Real mechanical strength
Chrome-moly steel with genuine strength and the option to harden. Pre-hard stock arrives at usable hardness, which removes a heat-treat step from the schedule.
- Typical use
- Shafts, gears, tooling, high-load mechanical components
- Watch out
- Slower cycles than aluminum. Specify annealed or pre-hard — they are different jobs.
Brass 360
Price in minutesHalf hard · The fastest metal through the machine
Cuts faster than anything else in the library, so a brass part can cost less than the same geometry in steel. Corrosion resistant and non-sparking.
- Typical use
- Fittings, valve bodies, electrical contacts, decorative hardware
- Watch out
- Soft. Not for wear surfaces or heavily loaded structure.
Titanium 6Al-4V
FlaggedGrade 5 · When performance outweighs price
The best strength-to-weight ratio of any common engineering metal, biocompatible and effectively corrosion-proof. It machines slowly and wears tooling, which drives most of its cost.
- Typical use
- Aerospace, medical instruments, motorsport
- Watch out
- Prototype in 6061 and switch once the design settles. The geometry lessons transfer; the cost doesn’t.
Delrin 150
Price in minutesAcetal homopolymer · The default engineering plastic
The most dimensionally stable of the common machinable plastics. It machines beautifully and runs against metal without lubrication.
- Typical use
- Bushings, gears, wear pads, insulators, manifold bodies
- Watch out
- Moves with temperature and moisture. Allow for it in your tolerances.
UHMW
Price in minutesSheet · bar · Impact and abrasion, cheaply
Extremely tough, low friction and nearly impossible to abrade. The right answer for wear strips, guides and anything that gets hit.
- Typical use
- Wear strips, chain guides, impact pads, conveyor components
- Watch out
- Not stable enough for precision fits. Loose tolerances only.
PEEK
FlaggedUnfilled · Plastic that survives the autoclave
High-temperature, chemically inert, sterilizable and strong — for when metal is out and ordinary plastics won’t survive the environment.
- Typical use
- Semiconductor handling, medical instruments, chemical service, insulators
- Watch out
- Material cost dominates the part cost, so an engineer sizes the stock before you’re quoted.
Polycarbonate
Price in minutesMachine grade · Transparent and tough
Impact resistant and optically clear. Used where someone has to see the mechanism, or where a guard has to survive being hit.
- Typical use
- Guards, windows, light pipes, inspection fixtures
- Watch out
- Scratches easily and can craze near solvents. Not a bearing surface.
Need something else?
Inconel, copper, magnesium or a specific temper — upload it anyway. Our team quotes it within two business days, with a committed ship date.
Shared stock lowers your price.
Stock runs in set thicknesses from 0.25 in to 4.5 in, in plate and bar. Every network shop draws from the same ladder, so your part and another customer’s can share a plate, a lot cert, a fixture and one setup.
Customer-supplied material is accepted with a cert. It’s flagged for review and doesn’t receive the batching discount, because we don’t control the lot.
Aluminum finishes: anodize, bead blast and powder coat.
Aluminum leaves the machine at 125 µin Ra by default, or 63 µin as a premium surface. Finishing is scheduled inside your order.
- Anodize Type II — clearThe default aluminum finish. Thin, hard, corrosion resistant.
- Anodize Type II — blackSame process, dyed. Other colors are flagged.
- Anodize Type IIIHardcoat. Thicker, for wear surfaces and sliding fits.
- Bead blastUniform matte, usually before anodize.
- Powder coatStandard RAL subset, for parts that live outdoors.
- Chem filmPartner-finished. Added days are stated on your quote.
Passivation, zinc plate and black oxide cover stainless and steel. See the full finish menu.
- 01
As-machined
125 µin Ra · default
- 02
As-machined
63 µin Ra · premium
- 03
Bead blast
Uniform matte
- 04
Anodize Type II
Clear
- 05
Anodize Type II
Black
- 06
Anodize Type III
Hardcoat
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