About Engineer’s Ephemeris
Engineer’s Ephemeris was built for mechanical engineers, machinists, and apprentices who need reliable answers fast. We combine practical calculators with clean reference tables so you can calculate, verify, and move on.
Free, accurate, and fast mechanical engineering calculators for machinists, students, and engineers.
Who I Am
I’m a mechanical engineer with a passion for precision and practical problem‑solving. I built this site after years of rewriting formulas, checking charts, and hacking together spreadsheets to speed up everyday machining and design work.
Why I Built This
Engineering often demands quick, reliable answers. Instead of flipping through handbooks or guessing at formulas, I wanted a central place where calculators are accurate, fast, and distraction‑free.
What You’ll Find Here
- CNC calculators: Speeds & Feeds, True Position, Sine Bar.
- Converters: KSI ⇆ MPa, Surface Finish (Ra, Rz, RMS).
- Reference tools: Standard drill sizes, threads, PCD coordinates.
- Geometry helpers: Arc geometry, right triangle, polar ⇆ cartesian.
My Philosophy
Every calculator is transparent about the underlying formula and designed to be used on the shop floor, in the classroom, or at your desk. Whenever possible, I add short guides and examples so you not only get a result, you understand it.
Let’s Connect
Have a suggestion, spotted an error, or want a new calculator? I’d love to hear from you. Email me or browse the full calculator index.