Sheet C-00 · Public resource

The Engineer’s Bench

Ten tools I built because I needed them. Free, no account, nothing logged, works offline once the page has loaded.

Every calculator states the equation it is using, the clause or textbook it comes from, and — more importantly — the point at which it stops being valid. A tool that will not tell you where it breaks is not a tool, it is a guess with a nice font.

10Tools on the bench

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SI/USBoth unit systems, converted at the edges only

∞Times you may use them commercially

Group 1Pressure & thermal

C-01

ASME VIII-1 pressure vessel

Minimum shell and head thickness per UG-27 and UG-32, MAWP from the wall you actually bought, joint efficiency and corrosion allowance, with the thin-wall validity limits enforced.

Open C-02

Cooling load & airflow

IT load to supply airflow and chilled-water flow, load per rack, duty per unit, and a straight answer about whether your N+1 is really N+1.

Open C-04

Heat exchanger sizing

LMTD with a computed Bowman correction factor and effectiveness–NTU side by side, plus fouling and a pinch warning where the area curve goes vertical.

Open C-06

Thermal expansion & restraint

Free growth, restrained stress, the force your restraint has to take, and how much of yield that spends before anything else is applied.

Open

Group 2Flow & mechanics

C-03

Pipe flow & pressure drop

Darcy–Weisbach with Colebrook–White iterated to convergence rather than approximated, minor losses, static head, and pump power at your efficiency.

Open C-05

Bolted joint & torque

Preload as a fraction of proof, seating torque through the nut factor, and the residual clamp left once the external load arrives — which is the number that matters.

Open C-09

Engineering unit converter

Ten families — length, pressure, force, power, flow, energy, torque, mass, area, velocity — every member shown at once instead of one at a time.

Open C-10

The circularity bench

Draw a circle freehand. A minimum-zone annulus is fitted to it and your circularity is reported as a real ASME Y14.5 value. Also, unexpectedly, a metrology lesson.

Open

Group 3Drawing office references

C-07

GD&T reference

All fourteen geometric characteristics with symbol, category, whether a datum is required and what the tolerance zone actually looks like — plus a feature control frame builder.

Open C-08

Welding symbol decoder

The anatomy of a welding symbol, then every common joint symbol with what it means on the shop floor and which side of the reference line it belongs on.

Open

Why these are free

My father gave his tools away.

Omenka ran a workshop where any young person who turned up could use the equipment. He never charged for the knowing part — only for the work. Later I helped start a makerspace in Nigeria on the same principle.

These calculators are the same idea in a different medium. Use them at work, use them in a quote, use them to check somebody else’s number. You do not owe me anything for it.

House rules

Nothing you type leaves your browser. There is no server to send it to.
No analytics, no cookies, no fingerprinting, no third-party scripts other than the web fonts.
Every tool shows its equations, so you can check the arithmetic by hand.
Every tool states where it stops being valid. Read that part.
These support engineering judgement. They do not replace a stamped design, a code calculation, or a competent reviewer.

Found something wrong? Tell me and I will fix it and credit you. That is how the workshop worked too.