Manufacturing Glossary
Plain-language definitions of the terms you’ll meet sourcing custom parts — from tolerances and tap drills to anodizing and RFQs — with links to the calculators, charts, and directories that go deeper.
Materials & grades
- Alloy
- A metal made by combining a base metal with other elements to tune strength, corrosion resistance, or workability (e.g., 4140 steel adds chromium and molybdenum).
- Temper
- The heat-treatment/work-hardening condition of a metal, especially aluminum (e.g., 6061-T6). Temper sets the mechanical properties.
- Mild steel
- Low-carbon steel (e.g., 1018) — soft, inexpensive, easy to machine and weld; not heat-treatable to high strength. 1018 vs 4140 →
- Stainless steel
- Corrosion-resistant steel with ≥10.5% chromium. 304 is the general-purpose grade; 316 adds molybdenum for chloride/marine resistance. 304 vs 316 →
- Heat treatment
- Controlled heating/cooling (annealing, quenching, tempering) to change a metal’s hardness, strength, and toughness. Alloy steels like 4140 respond strongly; mild steels barely.
- Hardness (HRC/HB/HV)
- Resistance to indentation. Rockwell C (HRC), Brinell (HB), and Vickers (HV) are common scales measured with different indenters and loads.
Tolerances & dimensions
- Tolerance
- The allowable variation on a dimension. Tighter tolerances cost more to hold. ISO 2768 chart →
- ISO 2768
- A standard for general (default) linear and angular tolerances applied to dimensions without an individual tolerance — called out by class (f/m/c/v). ISO 2768 chart →
- GD&T
- Geometric Dimensioning & Tolerancing (ASME Y14.5) — a symbolic language for specifying form, orientation, and location of features beyond simple +/- tolerances.
- Nominal dimension
- The target (ideal) size of a feature before tolerances are applied.
- Surface finish (Ra)
- The roughness of a surface, usually given as Ra (arithmetic mean roughness) in µm or µin, or as an ISO 1302 N grade. Surface finish chart →
Sheet metal
- Gauge
- A traditional thickness designation for sheet metal. The same gauge number is a different thickness in steel, aluminum, and stainless. Gauge chart →
- Bend allowance
- The arc length of material consumed in a bend, added to the flat flanges to get the correct flat-pattern length. Bend calculator →
- K-factor
- The ratio of the neutral-axis location to material thickness in a bend (~0.3–0.5). It drives bend allowance and varies with material and tooling. Bend calculator →
- Flat pattern
- The flattened (developed) shape of a sheet-metal part before forming, sized using bend allowance/deduction.
Machining
- CNC
- Computer Numerical Control — automated machine tools (mills, lathes) driven by a program to cut parts to spec. Cost estimator →
- Milling
- Machining with a rotating cutter that removes material from a workpiece, typically for prismatic (block-like) parts.
- Turning
- Machining on a lathe where the workpiece rotates against a cutting tool, used for round parts.
- Tap drill
- The hole size drilled before tapping an internal thread, chosen for a target percent thread. Tap & drill chart →
- Chamfer
- An angled (beveled) edge, used to break sharp corners or ease assembly.
- Fillet
- A rounded internal corner, which reduces stress concentration and is often required by the cutting tool radius.
- Deburring
- Removing the sharp burrs left by machining or cutting so edges are safe and parts fit.
Finishing
- Anodizing
- An electrochemical oxide layer grown on aluminum (and titanium) for wear/corrosion resistance and color; electrically insulating. Finishing guide →
- Powder coating
- A durable, colorful polymer finish applied electrostatically as dry powder and baked; works on most metals. Finishing guide →
- Plating
- Depositing a thin metal layer (zinc, nickel, chrome) for corrosion protection, wear resistance, conductivity, or appearance. Finishing guide →
- Passivation
- A chemical (acid) treatment of stainless steel that removes free iron and strengthens the natural corrosion-resistant layer — no coating or dimensional change. Finishing guide →
Sourcing
- RFQ
- Request for Quote — a buyer’s request to suppliers to price a part or job, usually with a drawing or model, quantity, and requirements.
- BOM
- Bill of Materials — the structured list of parts, materials, and quantities needed to build a product.
- DFM
- Design for Manufacturability — designing parts so they’re easier, cheaper, and more reliable to make.
- Lead time
- The time from placing an order to receiving the finished parts.
- MOQ
- Minimum Order Quantity — the smallest quantity a supplier will accept for a given part or price.
Ready to make something? Get quotes from U.S. suppliers, or browse the metals and finishing directories.
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