Free Engineering Tools
Interactive calculators and reference charts for mechanical engineers. Bookmark these tools for daily use—they're always free.
Tolerance Calculator
Determine achievable tolerances for CNC machining by process and material. Includes cost impact analysis.
Material Selection Guide
Compare 18+ engineering materials for machining. Interactive wizard helps you find the right material for your project.
Tap Drill Chart & Thread Reference
Complete thread reference with tap drill sizes, clearance holes, Helicoil specs, and torque values.
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Cost Estimator
Get ballpark machining costs by complexity, material, and quantity.
Surface Finish Guide
Ra/Rz conversion, finish photos, and process capabilities.
GD&T Reference
Symbol reference, datum selection, and common mistakes.
DFM Checker
Check your design for manufacturability issues.
Built for Engineers, By Engineers
Instant Results
No signup required. Get answers immediately without hunting through PDFs or outdated charts.
Real Data
Actual machining data from industry experience—not theoretical values from textbooks.
Always Free
These tools are free forever. Bookmark them and use them every day.
Ready to Get Parts Made?
Once you've finalized your design, find verified machine shops that can deliver quality parts on time.