About Machinist Central

Machinist Central is a free online resource for machinists, CNC programmers, toolmakers, welders and fabricators. It brings together the calculators, reference charts and know-how you normally have to dig out of a handbook, a tooling catalogue or an old notebook in the toolbox, and puts them in one place that works on a shop-floor PC, a tablet or a phone.

What you'll find here

• Machining calculators – speeds and feeds, tap drills, chip thinning, bolt circles, sine bars, thread wires, tolerance fits, surface finish, material weight and many more, all working in metric and imperial.
• G-code utilities – a G-code viewer, mirror and XYZ shift tools, subroutine and thread-milling generators, and engraving output for common controls.
• Articles & guides – in-depth explanations of the subjects machinists get asked about most: work offsets, cutter compensation, canned cycles, climb vs. conventional milling, chatter, workholding, reaming, GD&T and more.
• The Machinist's Handbook – quick-reference tables for tap and drill sizes, G and M codes, socket head and countersunk fasteners, wrench sizes and rivets.
• Fabrication and welding tools – sheet metal bend allowances, cone and box layouts, tube notching, weld volume, heat input and preheat calculators.

Why we built it

Most online machining calculators are buried under pop-ups, need an account, or only show an answer without explaining where it came from. Machinist Central is built the other way round: every tool is free to use without signing up, works in your browser without installing anything, and the formulas and assumptions behind the numbers are explained alongside the calculator so you can check the result and understand it.

How the content is made

Calculators are based on standard published formulas and reference data (ISO, ANSI/ASME and manufacturer data where it applies). Articles focus on practical, shop-floor explanations rather than theory for its own sake. When we find a mistake or a reader reports one, we correct it and update the page.

Even so, every machine, material, tool and setup is different. Treat our numbers as a well-reasoned starting point, check them against your tooling manufacturer's recommendations and your own experience, and always follow safe shop practice. See our Terms of Use for the full disclaimer.

How the site is funded

Machinist Central is free to use. To cover hosting and development costs, some pages show advertising served by Google AdSense. Ads are clearly labelled and kept separate from the tools and content. You can read how advertising cookies work in our Privacy Policy.

Get in touch

Spotted an error, want a calculator we don't have yet, or have a topic you'd like us to write about? We read every message. Visit our Contact page or email admin@machinistcentral.com.