Engineering reference data, design calculators, and material guides — built for working engineers who need answers fast. Free interactive tools, reference tables, and articles for working engineers.
Interactive Design Tools
O-Ring Groove Calculator
Calculate groove depth, width, and fill for static o-ring seals.
Tap Drill Size Lookup
UNC, UNF, NPT, and Metric tap drill sizes. Instant results.
Galvanic Compatibility Checker
Check corrosion risk between dissimilar metals.
Engineering Unit Converter
Length, pressure, torque, force, temperature, mass, area.
Beam Calculator
Shear, moment, and deflection diagrams with material and shape presets.
Drag Calculator
Aerodynamic drag force, power, and speed sensitivity for common shapes.
O-Ring Identifier
Measure an existing groove, find the right replacement o-ring from 250+ standard AS568 sizes.
Threaded Joints & Fasteners
- UNC Tap Drill Sizes
- UNF Tap Drill Sizes
- Metric Tap & Clearance Drills
- NPT Tap Drill Sizes
- UNC Thread Dimensions
- UNF Thread Dimensions
- NPT Sizes & Dimensions
- Hex Cap Bolt Dimensions
- Socket Head Cap Screw (SHCS)
- Bolt Grade Identification
- Hex Nut Dimensions
- Nut Grade Identification
- Flat Washer Dimensions
- Metric Hex Bolt Head Sizes
- Bolt Torque Chart (Grade 5, 8, SS)
- Fastener Preload & Torque
- Set Screw Torque Chart
- Clearance Hole Chart
- Thread Identification Guide
- Thread Engagement Length
Material Reference
- AISI/SAE Steel Numbering System
- International Steel Grade Equivalents
- Hardness & Tensile Strength Conversion
- Machinability of Metals
- Aluminum Alloy Comparison (6061/7075/2024/5052)
- Stainless Steel Types (304/316/303/410/17-4)
- Engineering Plastics (Nylon/Delrin/PEEK/PC)
- Young’s Modulus Chart
- Coefficient of Thermal Expansion (CTE)
- Sheet Metal Gauge Chart
- Wire Gauge Chart (AWG)
- Schedule 40 & 80 Pipe Dimensions
- Structural Steel Shapes (Angle/Channel/HSS)
- Galvanic Corrosion Guide
- Surface Finish Guide
O-Ring Design
- AS568 O-Ring Size Index — all 5 series
- Static O-Ring Groove Design Guide
- O-Ring Material Selection (NBR/FKM/EPDM/Silicone/PTFE)
- O-Ring Groove Calculator (interactive)
- O-Ring Identifier (interactive) — reverse-engineer from groove measurements
Mechanical Design
- GD&T Reference (ASME Y14.5)
- Tolerance Stack-Up Analysis
- Press Fit & Interference Fit Chart
- Bearing Selection Guide
- Shaft Design — Minimum Diameter
- Beam Deflection Formulas
- Compression Spring Design
- Stress Concentration Factors (Kt)
- Retaining Ring / Snap Ring Sizes
- Welding Symbols Guide (AWS A2.4)
- Keyway & Key Sizes
- Dowel Pin Sizes & Tolerances
- Master Drill Size Chart
- Metric to Inch Conversion