ENGINEERING RESOURCES

CNC Machining Resources: Engineering Calculators & Reference Charts

This is Baetro’s free engineering resources hub — 37 CNC and manufacturing calculators and 26 standards-based reference charts, all free to use with no registration. Every tool is standards-cited, engineer-reviewed, and backed by a manufacturer that actually machines the materials we chart.

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37 Engineering Calculators

26 Reference Charts

ISO Standards Referenced

Free No Registration

Find Engineering Answers Faster

Estimate costs, check tolerances, compare materials, and select the right parameters before manufacturing.

Cost Tolerance Materials GD&T

ENGINEERING CALCULATORS

All CNC & Engineering Calculators

Thirty-seven free engineering calculators, organized by the problems they solve. All are free, require no registration, and show the formula behind every result.

ENGINEERING REFERENCE CHARTS

All Reference Charts

Twenty-six standards-cited reference charts, organized the way engineers look things up. Every chart cites its governing standard, is print-friendly, and links to its companion calculator where one exists.

Tolerances & Fits

Tolerance Fit Chart ISO 286 hole/shaft tolerance bands and common fits ISO 2768 Tolerance Chart General linear and geometric tolerances Bearing Fit Chart Shaft and housing fits for bearings

Threads & Fasteners

Thread Pitch Chart Metric, UNC, UNF, and UNEF pitch series Thread Chart Pitch diameters and TPI reference Metric vs Imperial Thread Comparison M-series vs UNC/UNF/UNEF comparison NPT Pipe Thread Chart NPT taper thread dimensions Fastener Torque Chart Recommended torque by bolt grade

Drilling & Cutting Tools

Drill Bit Size Chart Fractional, number, letter, and metric sizes Drill Bit Decimal Equivalent Chart Decimal-inch and millimeter equivalents End Mill Size Chart End mill diameter reference Countersink Size Chart 82°, 90°, 100° dimensions

Materials & Properties

Material Properties Chart Density, strength, and modulus by material Material Hardness Chart HB/HRB/HRC/HV conversions CNC Material Machinability Chart Machinability ratings and parameters Copper & Brass Alloy Grades Chart CDA/UNS grades and properties

Surface Finish & Sheet Metal

Surface Finish Chart Ra/Rz/Rt roughness grades Sheet Metal Thickness Gauge Chart Gauge to thickness conversion Minimum Bend Radius Chart Bend radius by material and thickness Weld Symbol Chart AWS and ISO weld symbols

Hardware Components

Dowel Pin Size Chart Pin diameters and tolerances Retaining Ring & Snap Ring Size Chart Ring and groove sizes Anodizing Color & Thickness Chart Type I/II/III film thickness Wire Gauge Chart AWG diameter, area, and resistance

ENGINEERING APPLICATION

How Baetro Engineers Use These Standards

These reference charts are not just lookup tools. They are the same engineering standards our team applies when reviewing drawings, selecting materials, and preparing manufacturing solutions.

These charts aren’t decorative — they’re the same standards we apply on every quote. When you upload a CAD file, our engineers review it against exactly these references: ISO 2768 for general tolerances, ISO 286 for fits, ASTM E140 for hardness verification, and material data tables for property checks.

The purpose of these references is to help engineers make better decisions before manufacturing begins. Correct tolerance selection, material choice, surface finish requirements, and hardness specifications directly affect machining strategy, production cost, and final part performance.

ISO 2768

General tolerances for linear dimensions and geometry. Engineers use this standard to evaluate unspecified drawing tolerances and determine practical manufacturing requirements.

ISO 286

Hole and shaft tolerance systems used for fits and assembly requirements. It helps define clearance, transition, and interference fits.

ASTM E140

Hardness conversion reference used to compare HB, HRC, HRB, and HV values across different material testing scales.

Material Data References

Material properties such as density, strength, hardness, and machinability help engineers select suitable manufacturing processes.

From Engineering Reference to Manufactured Part

Drawing Review

Engineers analyze CAD files, dimensions, tolerances, materials, and finishing requirements.

Standard Verification

Requirements are checked against applicable ISO, ASTM, and engineering reference data.

Manufacturing Planning

Machining methods, tooling, inspection requirements, and production steps are defined.

Quality Inspection

Finished parts are verified with inspection reports and measurement equipment.

±0.001″ Standard Machining Capability

CMM Coordinate Measuring Inspection

ISO 9001 Quality Management System

AS9100 Aerospace Quality Standard

So when you look up a tolerance, hardness value, or material property here, you know two things: the data is based on recognized engineering references, and the manufacturer behind the data uses the same standards during real production.

Yes. All 37 calculators and 26 reference charts are free to use with no registration, no email capture, and no paywall. There’s no obligation attached — use them as often as you like.

Each calculator is built from standard engineering formulas and shows the formula with your values substituted, so you can verify the math. Data tables are compiled from governing standards including ISO 286, ISO 2768, ISO 965, ASTM E140, ASME B1.20.1, AWS A2.4, and Machinery’s Handbook. Results are engineering estimates for guidance — for critical applications, confirm against your drawing and standards.

Our standard capability is ±0.001 inch (±0.025 mm). Tightening tolerances increases cost, so we recommend specifying the loosest tolerance your design can accept. Our engineers identify over-tightened tolerances during DFM review because they are one of the biggest hidden cost drivers.

Cost is driven by material, machine time, setup, finishing, and tolerance requirements. Use the CNC machining cost calculator to estimate, then upload your CAD file for an exact instant quote. There is no minimum order quantity, so even a single prototype can be priced fairly.

Aluminum (6061, 7075) and brass machine fastest and generally cost less per part. Stainless steels (304, 316) and alloy steels (4140) require more machining effort. Titanium and hardened tool steels are among the most demanding materials.

The standard as-machined finish (Ra 3.2 µm / 125 µin) is suitable for many parts and included at no extra cost. Specify Ra 1.6 or finer only when required for mating surfaces, seals, or bearing applications, as finer finishes require additional processing.

Yes. Order 1 piece or 100,000 pieces. The process and quality standards remain the same, with no minimum order quantity and no tooling investment required for prototypes.

FROM ENGINEERING TO PRODUCTION

From Calculation to Machined Part

That’s the real point of this hub. A free calculator or chart gets you to a confident specification in minutes. Then the manufacturer behind the data gets it to your door.

60 Seconds Instant Quote

3–7 Days Standard Lead Time

No MOQ Prototype Friendly

CMM Inspection Reports

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