Praetore is a precision manufacturer with a distributed factory floor — one engineering core, a network of American shops on one standard, a price in minutes and a date backed by money.
Material choice sets a part's cost, weight, service life, and lead time before a single chip is cut. Most of what we make is aluminum, and most of that is 6061-T6 — because it is the right engineering answer more often than any other metal, not because it is the easy one.
The Catalog library is fixed and stocked. That is not a limitation we apologize for; it is the reason a price can be instant and a date can be underwritten. Below is every material in it, what each one is for, and where we would tell you to pick something else.
A count of the published library below — two aluminums in section 01 and eleven more in section 02 — not a claim about inventory on a given day. A material joins the library only under the rule in section 05.
Nearly every aluminum decision we see comes down to these two. 6061 unless the part is highly loaded; 7075 when it is and weight still matters. Both are stocked across the ladder, both price instantly, and both anodize.
T6 · Start here unless you have a reason not to
Strong enough for most structural parts, about a third the density of steel, excellent thermal conductivity, and it cuts fast — which is why it is also the cheapest to machine. It anodizes cleanly in clear or black, and it is the material stocked across the widest range of the ladder.
T651 · When 6061 is not strong enough
Roughly double the tensile strength of 6061 — into the range of many steels — while staying light. The default for aircraft structure and for anything highly loaded that still has to fly, ride, or be carried. It machines well, though it is less forgiving in thin sections.
Minimum wall in metals is 0.030 in and the minimum internal corner radius is 0.031 in, which accepts a 1/16 in end mill. Thin ribs and sharp internal corners are the two aluminum features most likely to flag a job for an engineer — usually with a one-line redesign suggestion attached.
Everything below is held on the standard stock ladder and prices from the same engine, and each entered the library under the rule in section 05 — proven feeds and speeds, real stock supply, and a committed recurring buyer. Two of them — titanium and PEEK — sit in a flagged tier, which means an engineer sizes the stock and confirms the price rather than a machine guessing at it.
Annealed · The free-machining stainless
Sulfur additions make 303 cut far more easily than the rest of the 300 series, at the cost of weldability. Pick it when the part is mostly machined features and never sees a weld.
Annealed · The one you weld
Tougher and more corrosion resistant than 303, and it welds cleanly. Pick it for welded assemblies, wet service, and anything a food-safety or marine spec is written against.
Cond A · H900 · Stainless that behaves like tool steel
Precipitation-hardening stainless that heat-treats to roughly 44 HRC in H900 while keeping its corrosion resistance. When a part must be hard, strong, and rust-proof at once, this is usually the answer.
Cold rolled · Cheap strength, honest work
Weldable, predictable, and inexpensive. The right answer for fixtures, brackets, and structural parts where cost wins and corrosion is handled by a coating.
Annealed · 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 leg from the schedule.
Half hard · The fastest metal through the machine
Free-machining brass cuts faster than anything else in the library, which often makes a brass part cheaper than the same geometry in steel despite the higher material cost. Naturally corrosion resistant and non-sparking.
Grade 5 · When the part matters more than the price
The best strength-to-weight ratio of any common engineering metal, biocompatible, and effectively corrosion-proof. Machining it is slow and hard on tooling — that is most of what you are paying for, and it is why titanium sits in a flagged pricing tier rather than the instant one.
Acetal homopolymer · The default engineering plastic
The most dimensionally stable of the common machinable plastics, it machines beautifully and needs no lubrication to run against metal. If a plastic part has to behave like a part, this is where to start.
Sheet · 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.
Unfilled · Plastic that survives the autoclave
High-temperature, chemically inert, sterilizable, and strong. Specified when metal is out for weight, electrical, or chemical reasons and ordinary plastics will not survive the environment.
Machine 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.
Need something the library does not hold — Inconel, copper, magnesium, a specific temper, a mill-certified customer lot? Send it anyway. It routes to the Sourcing lane, where a human comes back within 2 business days with a real answer and a committed date. Not a rejection, and not silence.
Standard stock runs in defined increments from 0.25 in to 4.5 in of thickness, in plate and bar. Every network shop draws from the same ladder, which means your part and a stranger's part can share a plate, a lot cert, a fixture family, and one setup.
No single shop sees enough order flow to do that. A network does. It is the machining equivalent of nesting several customers' parts on one sheet, and it is the reason staying on the ladder and inside the library shows up in your price rather than in a brochure.
Customer-supplied material is accepted with a cert. It flags the job and forfeits the batching discount, because we no longer control the lot, the size, or when it lands on the dock. That is a real trade, not a penalty — sometimes your lot is the whole point.
Aluminum leaves the machine at 125 µin Ra by default, or 63 µin as a premium surface. What happens after that is a fixed menu, scheduled inside your order rather than handed to you as a second project to manage.
Passivation, zinc plate, and black oxide cover the stainless and steel side of the library. The full finish menu lives on the capabilities page.
Adding a material to the Catalog means three things have to be true at once: proven feeds and speeds in the network, a real stock supply on the ladder, and at least one committed recurring buyer. Miss any of them and the material stays in the Sourcing lane, where a human quotes it honestly, until it doesn't.
Every out-of-library request is logged by class. That log is the expansion roadmap — the envelope grows from delivered evidence, never from marketing pressure. So tell us what you wish were instant.
The material spec and its lot requirement are two of the twelve artifacts inside every Job Packet, alongside the verified programs, the setup sheets, the tool list, the fixture plan, the probing routines and the inspection plan. A shop never has to decide what to cut it from — or chase a cert after the fact.
Apply as a shopLoading, environment, temperature, budget. In-envelope parts come back with a price and a guaranteed date in minutes, and the DFM feedback names any feature that would flag — in plain language, with the fix where one exists.
Upload a partThe material spec and its lot requirement arrive inside the packet, on stock from the shared ladder. We send you the job, not the RFQ — no quoting, no programming, no fees.
Apply as a shop