Free Manufacturing Tolerance Calculator - ISO 2768 & DIN 16742 Standards

Injection Molding, CNC Machining, Die Casting, 3D Printing Tolerances with Material Shrinkage Compensator

Professional tolerance calculator for engineers and product designers. Calculate accurate manufacturing tolerances for 50+ materials including ABS, nylon, polycarbonate, aluminum, steel across injection molding, CNC machining, die casting, and 3D printing processes. Based on ISO 2768, DIN 16742, and ISO 8062 international standards with automatic material shrinkage compensation for mold design.

Why Manufacturing Tolerances Matter

Every manufactured part has dimensional variation. No process can produce parts to exact nominal dimensions repeatedly. Understanding and specifying appropriate tolerances is critical for three reasons: parts must fit together (assemblies require mating tolerances), parts must function correctly (performance depends on dimensional accuracy), and cost increases exponentially with tighter tolerances (precision costs money in both manufacturing and inspection).

The fundamental rule of tolerance specification: Always design to the widest tolerance that still meets functional requirements. Unnecessary tight tolerances drive up manufacturing costs, slow production, increase scrap rates, and require expensive measurement equipment. Smart engineers specify tight tolerances only where truly needed for fit, function, or safety—and use standard tolerances everywhere else.

Understanding ISO 2768 for CNC Machining

ISO 2768 is the international standard for general tolerances on machined metal parts. When you machine aluminum, steel, or stainless steel on CNC mills and lathes, ISO 2768 defines what tolerances are achievable without special process controls. The standard has four tolerance classes:

• Fine (f): Tightest tolerances requiring precision equipment, skilled operators, and tight process control. Used only for critical mating features. More expensive due to slower machining speeds, more frequent inspections, and higher scrap rates.
• Medium (m): Standard tolerance class recommended for most CNC machined parts. Achievable by competent machine shops with normal process control. This is what most manufacturers quote by default. Good balance of cost, quality, and manufacturability.
• Coarse (c): Relaxed tolerances for non-critical dimensions. Faster machining, lower costs, acceptable for features that don't affect fit or function. Common for rough surfaces, clearance holes, non-mating surfaces.
• Very Coarse (v): Maximum tolerance for very large parts or dimensions where precision isn't needed.

For a 45mm CNC machined dimension: Fine tolerance = ±0.05mm, Medium tolerance = ±0.10mm, Coarse tolerance = ±0.30mm. That's a 6x difference between fine and coarse—directly impacting manufacturing cost and inspection requirements.

DIN 16742 for Injection Molded Plastics

DIN 16742 is the German standard specifically for injection molded plastic parts. It's widely adopted globally because it accounts for the unique behavior of plastics—material shrinkage during cooling, thermal expansion, moisture absorption, and flow direction effects. Unlike machined metals which start oversized and are cut to dimension, molded plastics start as molten material that shrinks as it cools.

DIN 16742 defines tolerances based on both part dimension and material shrinkage characteristics. High-shrinkage materials like polypropylene (PP) and acetal (POM) have wider tolerances than low-shrinkage materials like polycarbonate (PC) and ABS. Glass-filled plastics dramatically improve dimensional stability—30% glass fiber content can reduce shrinkage by 70% and tighten achievable tolerances by 40-50%.

Material shrinkage examples: ABS shrinks 0.4-0.7%, Polycarbonate shrinks 0.5-0.7%, Nylon 66 shrinks 1.5-2.0%, Polypropylene shrinks 1.5-2.5%, Acetal/POM shrinks 2.0-2.2%. For a 45mm dimension, that's 0.9mm shrinkage for PP vs. 0.27mm for ABS—directly affecting achievable tolerance and required mold cavity compensation.

The Parting Line Penalty - Critical Design Consideration

Injection molds and die cast tools consist of two halves that close together. The line where they meet is the parting line. Any dimension that crosses the parting line faces 75-100% worse tolerance than dimensions entirely within one half. This occurs because of unavoidable factors:

• Mold alignment: Even precision-ground molds have microns of misalignment between halves.
• Tool wear: Over thousands of cycles, parting surfaces wear, increasing gaps and misalignment.
• Thermal expansion: Mold halves expand at slightly different rates during production, shifting alignment.
• Clamping pressure variation: Inconsistent clamp force allows slight movement between halves.
• Physical gap: There's always a small gap at the parting line where flash can form.

Design strategy to avoid parting line penalty: Orient critical mating features entirely within one mold half. Run critical dimensions parallel to parting line rather than across it. Use mechanical locating features (pins, bosses, registers) rather than relying on parting line dimensions. If you must dimension across the parting line, specify wider tolerances and plan for potential secondary machining operations to bring dimensions back to specification.

Material Shrinkage Compensation for Mold Design

When plastic or metal cools from molten state to room temperature, it contracts. The mold cavity must be made larger than the desired final part dimension to compensate for this shrinkage. This calculator automatically computes required mold cavity size using the formula: Mold Cavity Dimension = Nominal Dimension × (1 + Shrinkage Rate).

Example: You want a 45mm dimension in final molded ABS part. ABS shrinkage = 0.5%. Mold cavity must be: 45mm × 1.005 = 45.225mm. When the part cools and shrinks, it will measure your target 45mm dimension. This is critical information for tool makers and mold designers.

Important notes on shrinkage: Actual shrinkage varies with wall thickness (thick sections shrink more), gate location and size (affects packing pressure and cooling rate), packing pressure settings (higher pressure reduces shrinkage), cooling time and rate (rapid cooling can lock in stresses), material grade and lot variation (different suppliers, different batches), and post-mold conditioning (some materials absorb moisture and swell).

For critical dimensions, always consult material supplier datasheets for shrinkage data specific to your grade and processing conditions. Consider mold flow analysis software (Moldflow, Moldex3D) for complex geometries. Run design of experiments (DOE) during mold qualification to optimize processing parameters and achieve target dimensions consistently.

Glass-Filled Plastics - The Tolerance Game Changer

Adding glass fiber reinforcement to plastics dramatically improves dimensional stability and tightens achievable tolerances. Glass-filled grades typically contain 15%, 30%, or 50% glass fiber by weight. The benefits for tolerance control:

• Reduced shrinkage: Glass fibers act as internal skeleton, resisting contraction during cooling. Unfilled Nylon 66 shrinks 1.5-2.0%, while Nylon 66 + 30% GF shrinks only 0.3-0.6%—that's 75% shrinkage reduction.
• Better dimensional stability: Less warping, more uniform shrinkage across part, reduced sensitivity to processing variations.
• Tighter achievable tolerances: 40-70% better tolerances compared to unfilled versions of same polymer. ABS tolerance ±0.25mm, ABS-GF30 tolerance ±0.15mm for same 45mm dimension.
• Improved strength and stiffness: Bonus benefits beyond dimensional control—higher tensile strength, greater rigidity, better creep resistance.
• Enhanced thermal performance: Higher heat deflection temperature, lower coefficient of thermal expansion.

Trade-offs to consider: Slightly higher material cost (typically 10-20% more), increased tool wear due to abrasive glass fibers, reduced impact strength (more brittle), potential surface finish issues (fiber show-through), and anisotropic properties (stronger in flow direction). For precision parts where dimensional accuracy is critical, glass-filled grades are almost always worth the trade-offs.

ISO 8062 for Metal Die Casting

ISO 8062 defines tolerance grades for metal castings including die casting, investment casting, and sand casting. Die casting (high-pressure injection of molten metal into steel dies) produces tighter tolerances than sand casting but not as tight as CNC machining. Common die cast materials include aluminum alloys (lightweight, good strength, excellent surface finish), zinc alloys (tightest tolerances, excellent detail reproduction, lower cost tooling), and magnesium alloys (lightest weight, good strength-to-weight, more expensive).

Die casting tolerances depend on part size, material, wall thickness, and die quality. For a 45mm dimension in aluminum die casting: Fine tolerance ±0.20mm, Standard tolerance ±0.30mm, Coarse tolerance ±0.55mm. Zinc die casting achieves slightly better: ±0.18mm, ±0.25mm, ±0.50mm respectively. Like injection molding, dimensions crossing the die parting line have worse tolerances due to die alignment and wear factors.

3D Printing Tolerances - Additive Manufacturing

3D printing (additive manufacturing) tolerances vary significantly by process technology:

• FDM (Fused Deposition Modeling): Melts plastic filament and deposits layers. Consumer and industrial machines. Typical tolerances ±0.30-0.50mm for standard parts. Affected by layer height, print speed, temperature control, material shrinkage during cooling. Lower cost but wider tolerances than other processes.
• SLA (Stereolithography): UV laser cures liquid resin layer-by-layer. Much better dimensional accuracy than FDM. Typical tolerances ±0.15-0.25mm. Excellent for prototypes requiring close-to-production tolerances. More expensive than FDM, limited material choices.
• SLS (Selective Laser Sintering): Laser fuses nylon powder particles. No support structures needed. Typical tolerances ±0.28-0.40mm but with high material shrinkage (3.0-4.0%) requiring significant part size compensation. Strong functional parts but surface finish rougher than SLA.
• MJF (Multi Jet Fusion): Similar to SLS but faster and more consistent. Becoming popular for production parts. Tolerances similar to SLS.
• Metal 3D Printing: DMLS/SLM processes for titanium, steel, aluminum, cobalt chrome. Tolerances ±0.10-0.20mm depending on geometry. Expensive but enables complex geometries impossible with traditional machining.

3D printing tolerance considerations: Build orientation affects accuracy (XY plane usually more accurate than Z-axis). Support structure removal can damage surfaces. Post-processing (machining, tumbling, vapor smoothing) can improve tolerances and finish. Thermal stress during build causes warping on large flat surfaces. Always verify critical dimensions after printing and budget for post-machining if needed.

Tolerance Stackup Analysis

When multiple parts assemble together, individual tolerances add up (stack up) affecting final assembly dimensions. Understanding stackup is critical for ensuring parts fit together reliably without excessive gaps or interference. Two methods for calculating stackup:

• Worst Case (Arithmetic) Stackup: Add all maximum tolerances together. Guarantees 100% parts will assemble but results in very conservative (expensive) tolerances. Used for safety-critical assemblies or very low production volumes where sorting/rework is acceptable.
• Statistical (RSS) Stackup: Uses root sum square method assuming normal distribution. Achieves balance between cost and quality. Typically results in 99.73% parts assembling correctly (3-sigma). More economical for high-volume production where occasional rework is acceptable.

Stackup reduction strategies: Minimize number of parts in tolerance chain (fewer parts = less stackup). Use datum features and geometric dimensioning & tolerancing (GD&T) to control critical relationships directly rather than through chains of basic dimensions. Design adjustability into assemblies (slots instead of holes, shims, adjustable fasteners). Specify tighter tolerances only on critical mating features—not every dimension. Consider selective assembly (sort parts into tolerance bands, match tight parts with tight counterparts).

Geometric Dimensioning & Tolerancing (GD&T)

This calculator provides general dimensional (linear) tolerances. For complex parts requiring precise control of form, orientation, location, and runout, use Geometric Dimensioning & Tolerancing (GD&T) per ASME Y14.5 (US standard) or ISO 1101 (international standard). GD&T provides more precise control with larger tolerances than traditional plus/minus dimensioning—reducing cost while improving quality.

GD&T tolerance types: Form controls (flatness, straightness, circularity, cylindricity), Orientation controls (perpendicularity, parallelism, angularity), Location controls (position, concentricity, symmetry), Runout controls (circular runout, total runout), Profile controls (profile of a surface, profile of a line). Each control applies to specific datum references, material conditions, and tolerance zones.

General rule of thumb for relating GD&T to dimensional tolerances: Form tolerances (flatness, straightness) typically 50-60% of dimensional tolerance. Orientation tolerances (perpendicularity, parallelism) typically 60-80% of dimensional tolerance. Location tolerances (position, concentricity) often equal to or slightly larger than dimensional tolerance. These are guidelines—actual geometric tolerances depend on functional requirements and manufacturing capabilities.

How to Specify Tolerances on Engineering Drawings

Professional drawing practice for tolerance specification:

1. General tolerance note: Include ISO 2768-m (or -f, -c) for machined parts, or DIN 16742 for molded parts in title block. This establishes default tolerances for all dimensions without specific callouts.
2. Specific tolerances: Directly dimension critical features with explicit tolerances: 45.00 ±0.10 or 45.00 +0.15/-0.05 (unilateral tolerance for mating features).
3. GD&T callouts: Use feature control frames for geometric requirements that plus/minus tolerancing can't adequately control.
4. Material specification: Include material grade, not just type: "Aluminum 6061-T6" not "aluminum". Different alloys machine differently and affect achievable tolerances.
5. Surface finish callouts: Specify Ra values in micrometers or microinches. Rougher finishes allow wider tolerances, finer finishes cost more. Typical: Ra 3.2μm for standard machined surfaces, Ra 0.8μm for precision mating surfaces, Ra 6.3μm for non-critical rough surfaces.
6. Heat treatment requirements: Specify if required (hardening, annealing, stress relieving) as heat treatment affects dimensions through thermal expansion/contraction.
7. Inspection requirements: Call out critical dimensions that require 100% inspection vs. sampling inspection vs. no inspection.

Tolerance Cost Reality

Manufacturing cost doesn't increase linearly with tolerance tightness—it increases exponentially. Halving tolerance typically doubles or triples manufacturing cost. Understanding this relationship prevents over-specification:

• Standard tolerance (ISO 2768-m): Baseline cost. Most machine shops achieve this with normal processes and standard inspection.
• Fine tolerance (ISO 2768-f): 2-3x cost increase. Requires slower machining speeds, more frequent tool changes, tighter fixturing, more measurements, higher scrap rates.
• Precision tolerance (±0.025mm): 5-10x cost increase. Requires temperature-controlled environment, precision grinders, CMM inspection, skilled operators, significant time per part.
• Ultra-precision (±0.005mm): 20-50x cost increase. Specialized facilities, diamond tooling, optical inspection, metrology expertise. Used only where absolutely necessary (precision instruments, aerospace, medical devices).

Tolerance-driven cost optimization strategy: Default all dimensions to standard tolerance class (ISO 2768-m for machining, DIN 16742 standard for molding). Identify truly critical dimensions—mating features affecting fit, safety-critical dimensions, features affecting product performance. Specify tighter tolerances only on these critical features. Document why each tight tolerance is necessary (fits bearing, controls alignment, prevents interference). Challenge every tight tolerance during design reviews—can you achieve same function with standard tolerance plus better design (locating features, compliance, adjustment)?

When to Consult Your Manufacturer Early

This calculator provides guidance based on industry standards and typical capabilities. However, actual achievable tolerances vary significantly between manufacturers based on equipment age and condition, operator skill level, process control maturity, quality system rigor, and workload/scheduling pressure. Best practice: send your design to 2-3 potential manufacturers early in design phase (before finalizing CAD, definitely before ordering tooling). Ask specifically: "What tolerances can you reliably hold on these features with your equipment and normal process control?" Most manufacturers appreciate early engagement and will provide honest capability assessments.

Red flags indicating manufacturer can't meet your tolerances: Reluctance to commit to specific values, vague responses about "we'll do our best", requesting significantly higher prices without explaining why, suggesting you loosen tolerances without understanding functional requirements, no statistical process control (SPC) or measurement system analysis (MSA) in place, no temperature-controlled inspection area for precision work.

Material Selection Impact on Tolerances

Choosing the right material directly affects achievable tolerances and dimensional stability:

• Low-shrinkage plastics: Polycarbonate (PC), ABS, Polysulfone (PSU) have excellent dimensional stability. Best choice for precision molded parts.
• High-shrinkage plastics: Polypropylene (PP), Acetal/POM, PVDF have wide tolerances. Use only when dimensional precision isn't critical, or select glass-filled grades.
• Glass-filled grades: 40-70% better tolerances than unfilled. First choice for precision plastic parts. Trade-off: higher cost, reduced impact strength.
• Engineering plastics: Nylons (PA6, PA66), PBT, PEEK offer good balance of mechanical properties and dimensional stability. More expensive than commodity plastics but better performance.
• Aluminum alloys: 6061-T6 most common for machining. Good machinability, tight tolerances, excellent surface finish. 7075-T6 for higher strength applications.
• Steel grades: 1018 mild steel for general machining. 4140 for high strength. Stainless 316 for corrosion resistance. All machine to similar tolerances but vary in difficulty (tool wear, cutting speeds).

Environmental Effects on Dimensional Stability

Parts manufactured to tight tolerances can grow outside tolerance in service due to environmental factors:

• Thermal expansion: All materials expand with temperature. Aluminum expands ~23 ppm/°C, steel ~12 ppm/°C, plastics 50-150 ppm/°C. A 100mm aluminum part grows 0.23mm over 100°C temperature rise—potentially exceeding tolerance.
• Moisture absorption: Nylons absorb 2-3% moisture by weight, causing dimensional growth of 0.3-0.5%. Dry-as-molded nylon parts grow in humid environments, potentially causing interference in assemblies.
• Creep and stress relaxation: Plastics under constant load slowly deform over time. Critical for snap fits, press fits, threaded assemblies. Use glass-filled grades or engineering plastics for load-bearing applications.
• UV degradation: Outdoor exposure causes plastics to shrink, crack, lose mechanical properties. Use UV-stabilized grades for outdoor applications.

Design strategies for environmental dimensional stability: Specify material grade with appropriate stabilizers (UV, heat, hydrolysis resistant). Design clearances accounting for worst-case thermal expansion across operating temperature range. Use materials with similar thermal expansion coefficients in assemblies to prevent differential expansion. Allow for moisture-induced dimensional growth in nylon parts through generous clearances or dry-as-molded dimensional specifications. Test prototypes in environmental chambers simulating worst-case conditions before production.

Quality Control and Inspection Methods

Verifying parts meet tolerance specifications requires appropriate measurement equipment and methods:

• Calipers (±0.02mm): Good for standard tolerances on simple features. Not suitable for tight tolerances or complex geometries.
• Micrometers (±0.001mm): Better for precision work. Outside mics, inside mics, depth mics for different features. Requires temperature control and skilled operators.
• Height gauges and indicators (±0.005mm): For flatness, perpendicularity, parallelism measurements on surface plates.
• Coordinate Measuring Machines (CMM) (±0.002-0.005mm): Sophisticated 3D measurement systems. Best for complex geometries, GD&T verification, statistical analysis. Requires temperature-controlled environment (20°C ±1°C) and trained operators.
• Optical comparators: Projects magnified part silhouette for profile comparison. Good for small parts with complex contours.
• Vision systems: Camera-based automated measurement. Fast for high-volume production. Good for 2D features, less accurate for 3D.
• Laser scanners and CT scanning: Non-contact methods for complex shapes. Expensive but becoming more common for quality verification and reverse engineering.

Measurement system analysis (MSA) is critical: Verify measurement system variation is small compared to tolerance (Rule of thumb: measurement uncertainty should be less than 10% of tolerance width). Perform gauge R&R studies to separate part variation from measurement variation. Calibrate equipment regularly to traceable standards. Train operators on proper measurement techniques.

Common Tolerance Mistakes to Avoid

• Over-specifying tolerances: Tightest possible tolerance "just to be safe" dramatically increases cost without functional benefit. Specify widest tolerance that meets functional requirements.
• Symmetric tolerances on mating features: Use unilateral tolerances (+0.15/0.00 or 0.00/-0.15) for shafts and holes to ensure proper fit direction and simplify tolerance stackup analysis.
• Ignoring parting line location: Placing critical dimensions across mold parting line guarantees wider tolerances. Orient critical features within one mold half.
• Forgetting material shrinkage: Specifying tight tolerances on high-shrinkage materials without compensating mold cavity size. Always account for material-specific shrinkage.
• No general tolerance note: Every drawing needs ISO 2768 or equivalent note establishing default tolerances. Otherwise, manufacturers guess what you want.
• Tolerance inconsistent with surface finish: Specifying ±0.02mm tolerance with Ra 6.3μm surface finish is contradictory. Fine tolerances require fine finishes.
• Not consulting manufacturer early: Finalizing design with tolerances beyond manufacturer capability creates expensive redesign delays. Engage manufacturers during design phase.
• Bilateral tolerances everywhere: Use unilateral (+0/-X or +X/-0) for mating features to control assembly clearance/interference precisely.

Advanced Tolerance Concepts

Statistical tolerance analysis: Monte Carlo simulation predicts assembly variation based on individual part tolerance distributions. More realistic than worst-case arithmetic stackup.

Tolerance allocation: Distributing total assembly tolerance budget across individual components. Tighten tolerances on inexpensive parts, relax tolerances on expensive parts to optimize total cost while meeting assembly requirements.

Design for Six Sigma (DFSS): Designing products and processes to achieve Six Sigma quality (3.4 defects per million). Requires understanding Cpk and process capability relative to tolerances.

Robust design (Taguchi methods): Designing products insensitive to manufacturing variation. Wide tolerances possible when design is inherently robust to dimensional variation.

Industry-Specific Tolerance Requirements

Automotive: PPAP (Production Part Approval Process) requires demonstrating process capability Cpk ≥ 1.33 for critical dimensions. Tight statistical control needed even for standard tolerances.

Medical devices: FDA requires risk analysis for dimensional variations affecting patient safety or device performance. Tighter control and 100% inspection often mandated for critical features.

Aerospace: AS9100 quality standard requires statistical process control and measurement system analysis. Tight tolerances with rigorous documentation and traceability for safety-critical parts.

Consumer products: Cost-driven optimization. Wider tolerances acceptable where appearance and basic function aren't affected. Focus tight tolerances only on features visible to consumers or affecting perceived quality.

Tolerance Calculator Features

• 50+ materials across injection molding, CNC machining, die casting, 3D printing
• ISO 2768 compliance for CNC machined metals (Aluminum, Steel, Stainless)
• DIN 16742 standards for injection molded plastics (ABS, PP, PC, PA6, PA66, POM, PBT, PEEK, PSU, PVDF)
• ISO 8062 standards for die cast metals (Aluminum, Zinc)
• 3D printing materials (FDM PLA/ABS, SLA resin, SLS Nylon PA12)
• Glass-filled plastic grades (ABS-GF30, PA66-GF30, PBT-GF30) with improved tolerances
• Automatic material shrinkage compensation calculator for mold design
• Parting line tolerance penalty adjustment (75-100% worse across parting line)
• Three tolerance classes: Fine (precision), Standard (recommended), Coarse (relaxed)
• Five size ranges: 0-25mm, 25-100mm, 100-250mm, 250-500mm, 500-1000mm
• mm/inch unit conversion with automatic calculation
• Percentage tolerance calculation
• Min/max dimension range display
• Standard reference shown for each material (ISO/DIN/Manufacturer data sources)
• Copy results to clipboard for documentation
• Detailed explanations of tolerance meanings and cost implications
• Design tips for optimizing tolerances and reducing cost
• Mobile-responsive design for use anywhere
• No login required—completely free forever
• All calculations performed in browser—no data uploaded to servers

Material Database Includes

Commodity Plastics: ABS (Acrylonitrile Butadiene Styrene), PP (Polypropylene), PC (Polycarbonate)

Engineering Plastics: Nylon 6 (PA6), Nylon 66 (PA66), POM/Acetal/Delrin, PBT (Polybutylene Terephthalate)

High-Performance Plastics: PEEK (Polyether Ether Ketone), PSU (Polysulfone), PVDF (Polyvinylidene Fluoride)

Glass-Filled Variants: ABS + 30% Glass Fiber, Nylon 66 + 30% Glass Fiber (PA66-GF30), PBT + 30% Glass Fiber

CNC Machined Metals: Aluminum 6061, Steel, Stainless Steel

Die Cast Metals: Aluminum, Zinc

3D Printing: PLA/ABS (FDM), Standard Resin (SLA), Nylon PA12 (SLS)

Getting Started with Tolerance Calculator

1. Select your manufacturing material from the dropdown (organized by category)
2. Review the applicable standard shown (ISO 2768, DIN 16742, ISO 8062, or manufacturer data)
3. Enter your part dimension (1-1000mm or 0.04-39.37 inches)
4. Toggle between mm and inch units as needed
5. Choose tolerance class: Fine (precision), Standard (recommended), or Coarse (relaxed)
6. If applicable to your process, indicate whether dimension crosses parting line
7. Review calculated tolerance (±mm or ±in) with min-max range
8. Note the standard reference and size range applied
9. Check material shrinkage percentage and compensated mold cavity dimension
10. Click Copy Results to save tolerance data to clipboard
11. Review design tips and comparison data for context
12. Always verify tolerances with your manufacturer before finalizing design

Free Tolerance Calculator—No Limitations

This professional tolerance calculator is completely free with no restrictions, no premium features, no required login, and no data collection. It's designed to help engineers, product designers, inventors, and manufacturing professionals quickly determine appropriate tolerances based on material, process, and international standards. The tool runs entirely in your browser—no calculations or data are sent to external servers. Copy your results and use them in your CAD software, engineering drawings, and design documentation.

Tolerance specification methodology is fundamental engineering knowledge refined over decades by standards organizations worldwide. This free tool makes professional-grade tolerance determination accessible to everyone committed to designing manufacturable, cost-effective products that fit together reliably.

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