Manufacturing Tolerances

A practical reference for engineers and buyers. Explore realistic tolerance ranges, why they matter by process, and how to design parts that quote quickly and build reliably.

CNC Machining Tolerance

Typical capabilities for milling and turning with guidance on ISO 2768 general tolerances, hole/shaft fits, straightness and flatness expectations, and how tool deflection, setup rigidity, and material choice affect achievable limits. Includes practical tips for datums, reaming vs. drilling, and when to call out GD&T to control critical features.

Metal Stamping Tolerance

Tolerance bands by feature type (holes, slots, tabs, profiles) and material thickness, with notes on burr height, punch-to-die clearance, bend radii, springback, and progressive vs. single-hit dies. Covers deep drawing specifics and why draw ratio, thinning, and corner radii dictate feasible ranges.

Sheet Metal Tolerance

Bend angle and flange length accuracy, minimum flange and hole-to-bend distances, inside radius guidance, K‑factor/neutral axis considerations, and flat pattern accuracy. Includes notes on laser/punch kerf, hole quality at small diameters, and post-weld distortion management.

Welding Tolerance

Straightness, flatness, angularity and gap control in welded structures per common fabrication classes (e.g., ISO 13920). Explains distortion drivers (heat input, sequence, restraint), joint design impacts (fillet vs. groove), and post‑weld corrective methods like stress relief and fixturing.

Metal Casting Tolerance

General casting tolerances (e.g., ISO 8062 CT grades) with practical allowances for sand, gravity, and investment processes. Discusses draft angles, pattern wear, core shift, and shrinkage allowances—and when to machine critical interfaces rather than rely on as‑cast control.

Metal Casting Surface Quality

Reference surface roughness ranges (Ra) and common cosmetic/functional defects: misruns, cold shuts, porosity, burn-on, and scabs. Guidance on gating/feeding influences and finishing expectations for sealing surfaces or coating prep.

Die Casting Tolerance

Aluminum and zinc die casting limits for basic size ranges with notes on parting line shift, ejector mark control, slide/movable core repeatability, and thermal balance. Highlights where die maintenance and venting affect dimensional capability and stability across shots.

Forging Tolerance

Closed‑die/open‑die forging allowances by size and weight, including draft angles, flash land, and trimming effects. Explains why grain flow and deformation lead to strong properties, and when to specify machining stock for critical bores, faces, or keyways.

Aluminum Extrusion Tolerance

Dimensional limits per circumscribing circle size and profile complexity with wall thickness, straightness, twist, and bow criteria. Covers enclosed spaces vs. open profiles, 5xxx series effects (e.g., 5052), and how die design and puller/tension settings influence outcomes.

Plastic Molding Tolerance

Injection molding tolerances driven by resin shrinkage, gate type/location, cooling balance, and part geometry. Practical ranges for amorphous vs. semi‑crystalline materials, guidance on bosses/ribs, and when to tighten with steel‑safe/tool‑adjustment strategy.

How to use this library

Start from the process your part is most likely to use, then refine your dimensions toward the mid‑range of the recommended tolerances for best cost, yield, and lead time. Tighten only what is functionally critical and call out datums and GD&T where needed. When in doubt, send your drawing—we can validate feasibility, suggest adjustments, and provide a fast quote.