MECHKIT
Mechanical know-how, applied — fasteners, torque, tolerances, and the DIY mechanics toolkit.
From setting a bolt’s torque and clamp load to sizing a gear reduction, laying out a belt drive, weighing a length of stock, and working out a cylinder’s push, MechKit pairs free hands-on calculators with clear, worked explanations. Get the number, and understand where it comes from.
Mechanical Calculators
Free tools for the workshop and the drawing board — a bolt torque calculator, a gear ratio & output speed calculator, a belt & pulley calculator, a material weight calculator, a hydraulic cylinder force calculator, and a thread & fastener size reference.
Bolt Torque Calculator
Get a tightening torque and clamp load from bolt size, property class, and lubrication — with the thread's tensile stress area, in N·m and lbf·ft.
Gear Ratio & Output Speed Calculator
Enter driver and driven teeth with an input speed to get the gear ratio, output rpm, and the torque multiplication a reduction gives you.
Belt & Pulley Calculator
From two pulley diameters, a driver speed, and the centre distance, work out driven rpm, belt speed, and the belt length you need to buy.
Material Weight Calculator
Estimate the mass of a bar, plate, or tube from its dimensions and material density — steel, aluminium, brass, and more — in grams, kilograms, and pounds.
Hydraulic Cylinder Force Calculator
Turn bore, rod diameter, and system pressure into extend and retract force, with piston and annulus areas — in kN, N, and kgf.
Thread & Fastener Size Reference
Look up coarse and fine pitch, tap-drill size, and tensile stress area for standard metric threads from M3 to M24, or compute the stress area for any thread.
Museum of Mechanics
Wander an immersive, richly illustrated collection — the history of machines from the lever to the steam engine, the gears and mechanisms that transmit motion, the engines and prime movers that make power, and the hand and machine tools that build it all, each in its own gallery. Every entry, image, and fact is drawn from Wikipedia and Wikimedia Commons.
Tour the museum →From the Workshop Journal
Clear, worked guides on bolt torque and preload, gear ratios, choosing the right fastener, reading engineering tolerances, belt versus chain drives, metal density and weight, and the basics of hydraulics — reading to pair with the calculators above.
Understanding Bolt Torque
Torque is only a proxy for the bolt tension that actually clamps a joint. Learn the T = K F d equation, why lubrication changes everything, and how to set preload.
Gear Ratios Explained
Count the teeth and you can predict output speed and torque exactly. This guide covers the ratio formula, a worked 3:1 example, gear trains, idlers, and the speed-torque trade-off.
Choosing the Right Fastener
Bolt, screw, or stud? Which property class, thread, head, and material? A practical walk through every decision that separates a joint that lasts from one that strips or corrodes.
Reading Engineering Tolerances
No part is ever made to an exact size, so drawings specify a range. Understand limits, deviations, clearance and interference fits, ISO IT grades, and why tighter tolerances cost more.
Belt vs Chain Drives
Belts grip by friction, chains engage positively, and that single difference decides which drive suits your machine. Compare efficiency, slip, noise, and maintenance in a side-by-side table.
Metal Density and Weight
Weight equals volume times density. Use a density table for common metals and a worked steel-bar example to estimate part mass before cutting anything, and see why it matters.
Keep Learning
Plain-language explainers on the fundamentals of mechanics — force and torque, fasteners and threads, power transmission through gears, belts, and chains, and the materials and fluid power that machines are built on — everything you need to go deeper with confidence.
Visit the Learn hub →