Engineering Guides
Plain-English explainers on the topics engineers actually have to get right — each links to the tools that do the maths.
Tolerancing & GD&T
GD&T Explained (Beginner Guide)
What geometric tolerancing is, the 14 symbols, datums, and bonus tolerance — in plain English.
How to Choose a Fit (ISO 286)
Clearance, transition or interference — picking H7/g6 and friends for bearings, dowels and press fits.
Tolerance Stack-Ups
Worst-case vs RSS vs Monte Carlo — will the gap actually close in production?
Tolerance Analysis in Practice
Defining the loop, gathering real tolerance data, choosing WC/RSS/Monte Carlo, and judging it against Cpk.
Reading Engineering Drawings
Views, title block, tolerances, surface finish and GD&T — how to decode a mechanical drawing.
Fasteners & Joining
Bolted Joint Design
Why preload matters more than torque, the nut factor, and designing a joint that survives fatigue.
Press-Fit & Shrink-Fit Design
Interference, contact pressure, holding capacity, and sizing the fit between slip and yield.
Snap-Fit Design (Interactive)
Why snap-fits are designed to strain, what the taper buys, and the roll-off failure nobody expects — with live widgets.
Welding
Reading Weld Symbols
Arrow side vs other side, fillet vs groove, and what the numbers on the symbol mean.
Choosing a Welding Process
MIG vs TIG vs stick vs spot — matching the process to material, thickness and volume.
Materials & Manufacturing
Sheet-Metal Design Basics
Bend allowance, K-factor, minimum flanges and holes — designing parts that actually fold up.
Design for Manufacturing (DFM)
Design parts that are cheap and easy to make — draft, radii, wall thickness, tolerances.
How to Select a Material
Strength-to-weight, stiffness, cost and corrosion — a practical way to narrow the field.
Heat Treatment & Hardness
Hardening, tempering, annealing and case hardening — and how hardness maps to strength.
Surface Finish & Metrology
What Ra and Rz mean, how a profilometer measures them, and how to specify finish sensibly.
Corrosion & the Galvanic Series
Why dissimilar metals corrode, the galvanic series, and how to stop it in a design.
Coatings & Plating
Anodize, zinc, passivation, powder, DLC — what each finish does and when to specify it.
Sealing an Enclosure
Why a sealed box ends up wet inside, what a temperature swing does to the gasket, and why the fix is a breather rather than a better seal.
Plastic Part Design (Interactive)
Why every rule is a ratio to the nominal wall — sink marks, draft, screw bosses and hinges, with live widgets.
Structures & Analysis
Fatigue: Why Parts Break
Cyclic loading, the endurance limit, stress concentrations and how to design against fatigue.
FEA Pitfalls
Mesh, boundary conditions, singularities and sanity checks — getting FEA you can trust.
Shear & Moment Diagrams
How to draw them, the sign conventions that trip people up, and what the shapes tell you.
Power & Motion
How to Size a Motor
Inertia, acceleration torque, RMS duty and the reflected-inertia trick with a gearbox.
Choosing a Bearing
Ball vs roller vs plain, load direction, speed, life and mounting — picking the right bearing.
Vibration Isolation
Natural frequency, the √2 rule, transmissibility and picking an isolator that actually helps.
Rotor Balancing in Practice
Balance grades, why the allowance halves with speed, and what a balancing machine actually does.
Fluids & Thermal
Getting a Convection Coefficient
Why h is the hard part of every thermal problem, and how to pick a correlation you can defend.
Duct Design Basics
Equal friction sizing, why velocity not pressure drop sets the limit, and what makes ducts noisy.
The True Cost of Compressed Air
Why it costs eight times what you think, where it leaks, and the fixes that actually pay back.
Reading a Combustion Analyser
What O₂ and CO₂ readings mean, how to tune excess air, and why net and gross efficiency differ.
Electrical
Sizing a Power Supply
Rails, headroom, inrush, efficiency and thermals — picking a supply that survives real loads.
Grounding & EMI
Ground loops, star vs plane, shielding and layout — why the motor kills your sensor reading.
Choosing a Motor Driver
Brushed vs BLDC vs stepper drivers — current rating, PWM, protection and feedback.
Reading a Datasheet
Absolute maximums vs recommended operating, typ/min/max, and the notes that bite you.
Choosing a Sensor
Range, resolution, accuracy vs precision, output type and how to condition the signal.
Aerospace
Random Vibration Basics
PSD, Grms, the 3σ rule and why random vibration is nothing like a sine sweep.
How to Write a Stress Report
Structure, load cases, margins of safety and the traceability a reviewer needs.
Aerospace Fastener Selection
MS/NAS callouts, grip length, edge distance, hole class and why AN/MS matters.
Composite Layup Basics
Plies, orientation, symmetry and balance — why a laminate warps if you get it wrong.
Marine
Designing in Marine Aluminium
Why 5xxx is plate and 6xxx is extrusion, what a weld costs you in strength, and the traps: sensitisation, filler choice, dissimilar metals.
Scantlings: Plate, Stiffener, Frame
How a pressure gets from the plating to the hull girder, and why stiffener spacing is the cheapest lever you have.
Dissimilar Metals in Sea Water
Why the area ratio decides the damage, not the metals; what to coat and what never to coat; and the upper potential limit an aluminium hull has.
Weight, Centres and the GM Budget
Why every weight needs a height, what a line item costs in GM, and the two margins that belong in the budget as rows rather than as reassurance.
Reference aids, not a substitute for engineering judgment.