Tools

The bench references I use constantly.

Quick, no-nonsense calculators and lookup tables for everyday hardware work, grouped by job. Free to use — bookmark whatever saves you a search.

Fasteners

Screw and nut sizing — dimensions, hole prep, holding force, and tightening torque, in metric and inch.

Dimensions, hole prep, and a three-view drawing for M2–M20 screws and nuts.

The same worksheet for #2–3/4in UNC/UNF screws and nuts.

Pick a screw by the load it must hold — safe working load for metric sizes.

Pick a screw by the load it must hold — safe working load for inch sizes.

How tight? Tightening torque, including what the tapped hole can take.

How tight? Tightening torque for inch sizes, hole strength included.

PCB and circuit math for board layout and bring-up.

Ten hobbyist PCB calculators on one page — trace width, vias, impedance, dividers, filters, shunts, and reference tables.