Engineering

Simple, Compound, Differential and Block Indexing

The dividing head and its arithmetic: the 40:1 worm heart, simple indexing worked across the plates, the compound trick of two motions, differential indexing with its gear train…

Soldering and Brazing

Joining metals with a molten filler without melting the parts: the soldering-versus-brazing line at 450°C, capillary action and the joint gap, why lap joints carry the load, the…

Engineering Mathematics13 Aug 2026 · 24 min read

Solution of Triangles

Engineering trigonometry reference: functions of angles, degree–radian conversion, right-angled and oblique triangle solutions, identities, computed function tables, interpolati…

Splines and Serrations

Splines and serrations as multi-tooth shaft-to-hub connections: straight-sided versus involute splines, why many teeth beat a single key, torque capacity from bearing area, fits…

Springs

Helical spring design: geometry and spring index, rate and deflection, shear stress with the Wahl correction, ends, solid height and buckling guidance, stored energy, and notes …

Spur Gears

Spur gear fundamentals: the involute tooth and why it is used, module and diametral pitch, the pitch, base, addendum and dedendum circles, pressure angle, gear ratio and centre …

Standard Steels

Carbon and alloy steels for engineers: what carbon does, the SAE/AISI four-digit designation system and how to read it, the alloying elements and their effects, the carbon equiv…

Standard Tapers

Machine tool tapers: how a taper is defined, self-holding tapers such as the Morse that grip by friction, self-releasing steep tapers held by a drawbar, the self-locking angle c…

Surface Texture

Surface finish: roughness, waviness and lay, the Ra average and Rz peak measures with computed examples, stylus measurement and cutoffs, typical roughness by process, the N-grad…

Symbols and Abbreviations

Writing measurements correctly: the grammar of SI symbols, case sensitivity, spacing and compound units, the base-unit and prefix symbols, the Greek alphabet as used in engineer…

T-Slots, T-Bolts and T-Nuts

The workholding interface of every machine table: the T-slot family, the strap clamp as a lever and why bolt position doubles or halves the clamping force, and the computation s…

Tapping and Thread Cutting

Cutting the thread by hand and by machine: the taper-plug-bottoming tap set, spiral-point and forming taps, dies and chasers, single-point threading on the lathe, and the consta…

Taps

Cutting internal threads with taps: the tap-drill size and percentage thread engagement, cutting versus forming taps, taper, plug and bottoming taps, flute types for through and…

Thread Grinding

The precision end of thread making: a diamond-dressed wheel carrying the thread's negative, single-rib and multi-rib practice, the tilt-to-the-lead-angle geometry, why hardened …

Thread Milling

The CNC way to a thread: a rotating cutter driven around a helical orbit, the geometry worked for an M20 with a twelve-millimetre tool, the 2.5× feed correction that scraps thre…

Thread Rolling

The thread that is squeezed, not cut: why the blank is exactly the pitch diameter, the machines from flat dies to planetary heads, the fatigue case for rolled roots and grain fl…

Tool Steels

Tool steels for cutting, forming and dies: what sets them apart from structural steel, the AISI letter-grade groups (W, O, A, D, H, M, T), red hardness and wear resistance, and …

Tool Wear and Sharpening

How cutting tools wear and when to regrind: flank and crater wear, the wear mechanisms of abrasion, adhesion and diffusion, the flank-wear limit as a life criterion, the speed–l…

Mechanical13 Aug 2026 · 6 min read

Torque and Tension in Fasteners

What tightening a bolt actually does: preload as the purpose, the torque-tension relation and its unreliable friction factor, how little of the applied torque becomes tension, t…

Transmission Chains

The positive drive between belt and gear: roller-chain anatomy as a string of tiny plain bearings, chordal action worked across the tooth counts, chain speed and the pitch serie…

Twist Drills and Counterbores

Drilling holes with the twist drill: point and helix angles, the chisel edge and thrust, speed and feed, and the counterbores, countersinks and spotfaces that finish a hole for …

Unified Screw Threads

The inch 60° system: how wartime incompatibility produced the Unified compromise, the basic profile from H = 0.866p, reading a designation, coarse against fine worked at half an…

Mechanical13 Aug 2026 · 6 min read

US and Metric System Conversions

Converting between US customary/imperial and metric units: the exact inch and pound that anchor every factor, computed conversion tables for length, mass and force, pressure and…

Mechanical13 Aug 2026 · 6 min read

Welding

Joining metal by fusion: how welding melts the parts together with a filler of like composition, the main arc processes, heat input and its calculation, the heat-affected zone a…

Whitworth Threads

The 1841 original: the fully radiused 55° form, its geometry worked at quarter-inch BSW, what the radius buys in fatigue and sealing, why 55° never mates with 60°, and where the…

Wing Nuts, Wing Screws and Thumb Screws

The fasteners tightened by hand: wing nuts, wing screws, thumb screws and knurled heads, the computation of what finger torque actually achieves on a thread, and the design cons…

Worm Gearing

Worm gearing for high single-stage ratios on non-intersecting right-angle shafts: the worm and wheel, lead and lead angle, ratio, centre distance, the self-locking condition, sl…

Civil & Structural13 Aug 2026 · 10 min read

Window & Door Hardware — Durability and Corrosion Resistance (ICP-002)

A practitioner's guide to Industry Code of Practice ICP-002 — how the corrosion resistance and cyclic durability of window and door hardware for housing and residential building…