About & methodology

MachineCalcs is an independent collection of engineering calculators. It does not sell springs, cylinders, gears, ductwork, conduit, lumber or machining services, so the page is not optimized to steer a result toward a quote form. The calculator is the product: enter dimensions, see the computed result, and inspect the method that produced it.

How a calculator is built

1. Define the engineering scope, inputs, outputs, assumptions and units before a page is built.
2. Implement the formula in a typed calculator module, then render the same module in the browser UI.
3. Add warnings, soft limits, verdicts and notes where a result depends on a convention or simplified model.
4. Back the page with regression tests, search aliases, related-tool links and maintenance notes.

Each calculator implements published engineering relationships or clearly disclosed screening equations in a local TypeScript module. The same computation runs when the page loads and when an input changes, so default examples are not hand-written marketing numbers. Where a result depends on a convention such as spring end type, gear tooth system, conductor fill basis, duct roughness, load case or cylinder efficiency, the page states the assumption near the result or in the method section.

• Springs follow standard helical-spring design practice (spring rate, Wahl stress correction, solid height, and the slenderness buckling criterion).
• Hydraulics use the pressure-times-area force relations, with the rod-area differential between push and pull shown explicitly.
• Gears use standard full-depth involute geometry, including the inverse-involute solution for profile-shifted center distance.
• HVAC tools use transparent furnace-capacity, airflow, sensible-load, air-change, grille free-area, Darcy-Weisbach and static-pressure budget checks, with final design caveats for ASHRAE, ACCA, SMACNA, manufacturer data and local code.
• Electrical raceway tools use conductor and conduit area checks with explicit adopted-code, local-amendment and manufacturer-dimension caveats.

Where the data comes from

Embedded reference tables and constants are compiled from recognized engineering references, standards, manufacturer-style tables and common design handbooks. Examples include ASTM wire standards, ISO 6020-2 cylinder dimensions, ISO gear module series, NEC-style conduit-fill area limits, ASME/ISO fit tables, steel pipe schedules and material-density references. When a page uses table data, the visible table and the calculation module use the same values.

Review and testing policy

MachineCalcs publishes as an independent software publisher. A page is not presented as professionally sealed or PE-reviewed unless a named reviewer is explicitly shown on that page. The current review process is software and calculation focused: formulas are implemented in isolated modules, regression tests cover expected values and edge cases, UI tests cover calculator behavior, and build checks validate every generated static page before deployment.

Pages are updated when a formula bug is found, when a table needs maintenance, when a calculator is expanded with a better warning or output, or when Search Console and analytics show that users are trying to solve an adjacent job. Structured metadata keeps the maintenance date available to crawlers without adding a visible timestamp to every page.

Limitations & safety

These are reference tools. They use typical published values and simplifying assumptions, such as static loading for many strength checks, theoretical pressure-area force before side-load effects, simple beam models, or first-pass duct and electrical screens. They are not a substitute for a qualified engineer's review on safety-critical or load-bearing designs. For production work, verify every value against the governing standard and your supplier’s certified data, and have the design reviewed by a qualified professional. We document each tool's assumptions in its method, notes or caveats section.

Accessibility

The calculators are built to work with a keyboard and screen reader: inputs have explicit labels and units, validation messages are announced without blocking the calculation, conditional fields are removed from the accessibility tree when hidden, and generated charts include text metadata plus visible captions. Copy/share actions use live status text so clipboard success or failure is announced.

Privacy & analytics

MachineCalcs uses minimal Google Analytics 4 measurement to understand which pages and calculator categories are actually useful. Calculator events are limited to coarse actions such as default result views, FAQ/disclosure toggles, first use, first field focus, visible-time engagement, session summaries, scroll depth, unit changes, validation warnings, copied results, copied summaries, copied links, site-navigation clicks, related-tool/reference clicks, embed-code copies and DXF downloads. Homepage search analytics count query length, token count and result count, but do not send the raw search text. We do not send your calculator input values, dimensions, results, copied summaries, URLs, link text or embed snippets to analytics. Google signals and ad personalisation signals are disabled in the site tag.

Corrections

Found a value or formula you'd question? That is the most useful thing you can send us — accuracy is the whole point. Email [email protected] with the tool and the reference, and we’ll review and correct it.